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LIBRARY OF CONGRESS. J 

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I UNITED STATES OF AMERICA, f 



coi 6 1887 



ELEMENTARY CHEMICAL TECHNICS 



A HANDBOOK OF 



MANIPULATION AND EXPERIMENTATION 



TEACHERS OF LIMITED EXPERIENCE, AND IN SCHOOLS 

WHERE CHEMISTRY MUST BE TAUGHT WITH 

LIMITED APPLIANCES 



BY. 

GEORGE N. CROSS, A. M., 

PRINCIPAL OF THE ROBINSON FEMALE SEMINARY. 



fa* 





BOSTON 

SILVER, ROGERS, & CO., PUBLISHERS 

50 Bromfield Street 

1887 






Copyright, 1887, 
By GEORGE N. CROSS. 



PREFACE 



The office of this little book is expressed in its title. 
My faith that such a work may be of some service in 
the cause of science teaching, is founded in part upon 
a realization of what a valuable adjunct such a book 
would have been in the earlier years of my own teaching. 

No attempt has been made to write a text-book of 
Chemistry. There are enough good works of that nature 
to meet the requirements of every school. But from 
a proper regard for brevity, and sometimes from a lack 
of appreciation of the teacher's needs on the part of 
authors, text-books fail to give that careful detail of 
direction which will insure success in experimentation. 

In the chapter on the Metals I have made no mention 
of the more rare ones, considering only such as are likely 
to be worked with in the ordinary school courses. 

The terms of both the English and Metric systems 
are used, for I find that the two systems are used about 
equally in schools, and the tables provided in text-books 
render the conversion from one system to the other an 
easy matter. 



111 



IV PREFACE. 

I wish to express my indebtedness to Prof. A. C. 
Boyden of the Bridgewater Normal, and to Mr. H. W. 
Tyler of the Massachusetts Institute of Technology, 
who have read the manuscript and proof-sheets, and 
given me valuable suggestions in my work. 

GEORGE N. CROSS. 
Exeter, N. H., May 25, 1887. 



CONTENTS. 



PAGE 

CHAPTER I. 
Construction and Equipment of Laboratories . . 1 

CHAPTER II. 
Glass Working v . 18 

CHAPTER III. 
Construction of Apparatus 24 

CHAPTER IV. 
General Manipulations 35 

CHAPTER V. 
Experimentation with Hydrogen, Oxygen, Water, and 
Air 4A 

CHAPTER VI. 

Experimentation with Nitrogen Compounds . • 55 

CHAPTER VII. 
Fluorine, Chlorine, Bromine, and Iodine, and ■M|eib 

Compounds 59 

v 



VI CONTENTS. 

CHAPTER VIII. 
Experimentation with Carbon and its Compounds . 66 

CHAPTER IX. 
Sulphur, Phosphorus, Arsenic, Antimony, Boron, Sili- 
con, AND THEIR COMPOUNDS 76 

CHAPTER X. 

Experimentation with the Metals and their Com- 
pounds 86 

CHAPTER XI. 
Spectrum Analysis 100 

CHAPTER Xn. 
Electricity in Chemical Reactions .... 104 



ELEMENTARY CHEMICAL TECHNICS. 



CHAPTER I. 

CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 

1. An apartment devoted exclusively to the purpose 
is not only a great convenience, but an absolute necessity, 
in the successful teaching of Chemistry. Neatness, con- 
venience, health of pupils and teachers, the risk of injury 
to physical and other kinds of apparatus, and to school 
furniture from the use of chemicals in ordinary school- 
rooms, and an encouraging degree of success in experimen- 
tation, all demand such a room in every school where 
Chemistry is taught. 

2. Selection of Rooms. — Rooms upon the highest floor 
of a school-building possess some advantages in the way 
of ventilation, without the danger of vitiating the air of 
apartments above. But ground-floors and basements of- 
tener furnish the desired accommodations. 

The apartment should be large, high-studded, and well 
lighted by several windows extending nearly to the ceil- 
ing. The windows should all open both at top and bottom 
for a quick change of air. Besides this it must have a 
large ventilator, with a strong draught, and adequate means 
of heating. An abundant supply of soft water is an 
absolute necessity in all chemical manipulations. Con- 

1 



2 ELEMENTARY CHEMICAL TECHNICS. 

venience in obtaining and drawing it off after using must 
be studied. Equally important is a safe and economical 
means of heating retorts, flasks, evaporating-dish.es, etc., 
available for each pupil. 

3. The two Laboratories. — It may be well to describe 
minutely the furnishing and equipment of two small lab- 
oratories : the first constructed at trifling expense, but 
of great practical service ; the second somewhat more 
elaborate and better equipped, but still within the means 
of the majority of public and private schools. Both are 
descriptions of laboratories actually built and successfully 
used, and the quotations of figures are real ones, from the 
carefully kept accounts of construction. In both, provi- 
sions are made for the individual work of twelve pupils. 
Of course the dimensions of apartments and the present 
and prospective requirements of schools will modify these 
calculations. 

LABORATORY No. 1. 

We will proceed on the supposition that the building 
in which this laboratory is to be fitted up is supplied with 
neither water nor illuminating-gas. These desiderata must 
be supplied as well as possible. 

4. Water Supply. — Obtain a sound, strong molasses- 
hogshead (with iron hoops, if possible). Eemove one 
head, and set upon a strong platform of planks thirty-six 
inches high, in a corner of the room, and near a window. 
Get a tinman to conduct the water from the roof into the 
hogshead. This can be done through the window, by re- 
moving a pane of glass, and inserting in its place a piece 
of tin, perforated for 'the admission of the tin conductor. 
From a point three inches below the top of the hogshead 
carry out through the tin " pane " a waste-pipe of the same 
size as the conductor. Obtain a piece of gas-pipe as long 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 3 

as the distance from the hogshead to the end of the room. 
Have iron faucets fitted to the end and middle of this 
pipe, and by means of it carry water from the hogshead 
the length of the room at a height of three and one-half 
feet from the floor. If desirable, turn an iron faucet into 
the hogshead itself, and water can be drawn in three differ- 
ent parts of the room at once. The waste water can be 
poured into large earthen crocks provided for the purpose, 
collected at the close of the exercise and carried out. 

5. Heating. — In lieu of Bunsen burners and gas, small 
glass lamps, burning alcohol, will be used for heating pur- 
poses. 

6. Laboratory Table. 

DIMENSIONS. 

FT. IN. 

Length 12 6 

AYidth 4 4 

Height 3 

Height of partition b b . . 1 G 

" " shelf a a . . .09 

Width of shelf a . . . 6 

Height of shelves c c c . .20 

FlG.I. 

Fig. 1 represents a very convenient table adapted for 
twelve pupils. Each side is divided into three sections, 
each section being used by two pupils in common. Such 
an arrangement has many advantages. With every facil- 
ity, abundant apparatus and chemicals, there is a great 
gain in providing for pupils in general chemistry to work 
in pairs. They are mutually helpful in the at first trouble- 
some manipulations, and the saving in amount of apparatus 
and quantity of chemicals by such an arrangement is very 
considerable. 

The figure will for the most part explain itself. It 
should be made of -J pine stock, comparatively "clear." 
The top should be left unpainted. The remainder can be 



b 






b 


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4 ELEMENTARY CHEMICAL TECHNICS. 

painted, or, better, covered with several coats of hard oil 
finish, or left in the natural condition, as taste and funds 
may direct. The shelf a a, and the space upon the table 
beneath, will be used for bottles and small pieces of appara- 
tus. The partition b b should be carried down through 
to the floor, dividing the table into lateral halves. The 
shelves c c c below are for larger pieces of apparatus, and 
each pupil's private effects. Under the shelf in each sec- 
tion can be placed an earthen crock for the reception of 
waste water and other matter. 

7. Storage Closet. — This should be made of the same 
well-seasoned stock as the table, with joints close fitting 
enough to keep out all dust. Convenient dimensions will 
be 8 feet in length, 7 feet in height, and 1 foot 5 inches 
deep. A central partition should divide the case into two 
sections. One side will be fitted up for the storage of 
chemicals. Leaving ample space in the bottom for the 
reception of large bottles of acids, let the upper part of 
the section be provided with shelves made each with three 
ledges, one above and back of another, like the successive 
steps in a flight of stairs. These ledges, about three inches 
in height, will be a great convenience in the arrangement 
of bottles of different sizes, placing the largest upon the 
highest ledges. 

The other section will receive the glassware and appara- 
tus, and can be made convenient by means of plain, deep 
shelves at suitable distances from each other. 

8. Lecture Table. — There should be sufficient space in 
the room chosen for a laboratory, or an adjoining one, for 
the recitations on the subject, and the lecture table should 
be conveniently placed in this room. Such a table is indis- 
pensable for the performance of general class experiments, 
not profitably to be given to the members of a class, for 
illustrations in the course of a recitation, and as furnishing 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 5 

a deep tank necessary in the transferring of gases from one 
vessel to another. 

For illustration of such a table see Fig. 3. The table for 
Laboratory No. 1 is of the same general construction as the 
one described in Section 14, but may be made of cheaper 
materials and painted in a less expensive manner. Con- 
siderable expense may be saved by building, instead of the 
drawers, plain lockers, and the convenience of these may 
be enhanced by putting a horizontal shelf through the 
middle of each locker. 

9. Hood. — A close box or hood, within which all opera- 
tions involving the generation of poisonous gases can be 
carried on, should be a part of the equipment of every labo- 
ratory. This box should be well lighted, constructed so 
tight that no gas can escape into the room, and arranged 
to conduct the gases generated either into a ventilator-box, 
with an unfailing upward draught, or directly to the open 
air through a window. In Section 16 is described a very 
perfect but somewhat expensive hood. An excellent sub- 
stitute is the following: 

Make a box-frame of f pine stock 18 inches deep, of such 
dimensions as to be set within the frame and fit up closely 
against the sash of the window least used in the labora- 
tory. Purchase a glazed sash of the size of the inside 
dimensions of the box-frame and arrange it to slide up and 
down in one side of the frame like a window. With hooks 
on the box and screw-eyes in the lower sash of the win- 
dow, clamp the box closely to the window so that the lower 
window-sash shall form one side, and the new sliding sash 
the other side of a tight box. Fit into the top of the box 
an elbow-joint of small stove-pipe, and pass this pipe out 
through the upper sash by removing one of the panes of 
glass and substituting a piece of tin perforated for the 
passage of the pipe. For ventilation of the box bore 



6 ELEMENTARY CHEMICAL TECHNICS. 

several holes in the lower rail of the window-sash, and, to 
insure an upward draught, a little more than half-way up 
on one of the wooden sides of the box place a lamp-bracket, 
and set a lighted kerosene lamp in the bracket whenever 
the hood is to be used. The cost will be about $2.50. 

10. Equipments. 

Apparatus and Glassware. 

Alcohol lamps. (See section 45.) 

Aspirators. (See section 30.) 

Bags for gases. (See section 32.) 

1 dozen beakers, 2£ ounces, at .15 . . . . $ 1.80 

Bell-jars, tubulated. (See section 38.) 

Mouth blowpipes. (See section 46.) 

Gas-bottles (horseradish bottles, etc., from home). 

3 dozen 4-oz. bottles, with ground stoppers, at $ 1.35 4.05 

1 dozen one-quart fruit-jars 1.50 

Book of chemical labels 50 

6 clamps for test-tubes. (See section 36.) 

6 earthen crocks 72 

10 dozen assorted corks . . . . . . 1.20 

Cover glasses. (Cut up pieces of broken window- 
panes into squares 4x4 inches.) 
Se* of cork-borers. (See section 41.) 

2 j*und files 40 

1 shoekaife for cutting corks .... .35 

1 flat file .35 

6 Hessian crucibles, 4£-inch .60 

6 deflagrating spoons. (See section 42.) 

6 porcelain evaporating-dishes, 3-inch .. . .1.50 

1 pack of filter-paper, 6-inch .40 

4 flasks, flat bottomed, 8-ounce 1.85 

12 flasks, flat bottomed, 4-ounce . . . . 1.20 
6 glass funnels, 3-inch 90 

2 lbs. glass-tubing (assorted numbers) . . . 1.00 

2 graduates, 4-ounce 80 

6 large nappies (for pneumatic pans) . • . 2.10 
Generators for hydrogen, etc. (See section 31.) 

Amount carried forward . . . $21.22 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 

Amount brought forward . . . $21.22 

3 Wedgewood mortars, 3-inch 2.40 

Platinum wire, | pwt .30 

foil, |pwt 30 

2 potash bulbs (one bulb) .80 

1 iron retort 3.00 

24 feet rubber-tubing, T 5 g-inch 1 3.60 

1 pair of scales, platform 5.00 

6 retort stands. (See section 35.) 

3 dozen test-tubes, 6-inch 1.08 

6 thistle-tubes 72 

6 testrtube brushes. (Tie pieces of fine sponge to a 

stout wire.) 

3 U-tubes, 4-inch 75 

Wash-bottles. (See section 43.) 

Wire gauze, 1 square foot 50 

Lead-pan. (Make it from sheet-lead, as directed for 

making sand-bath. See section 39.) 

Total $39.67 

Chemicals. 
Alcohol, 2 quarts. (Price variable.) ... $ 1.20 

Alum, 8 ounces 05 

Aqua ammonia, 1 pound .20 

Ammonium chloride, 1 pound 25 

Ammonium nitrate, 1 pound . . . . . . .40 

Antimony, metal, 4 ounces 10 

Arsenious acid, 2 ounces ...... .10 

Bone-black, 1 pound 30 

Calcium chloride .40 

" sulphate, 1 pound 10 

Camphor, £ pound .25 

Carbon disulphide, 1 pound 50 

Chlorhydric acid, 5 pounds .35 

Cochineal, 2 ounces 10 

Copper-filings, \ pound .25 

" oxide, 1 ounce 20 

" sulphate, 1 pound .12 

Amount carried forward ... $ 4.87 

1 Some tubing of a smaller size may be used for connection. 



ELEMENTARY CHEMICAL TECHNICS. 

Amount brought forward . . . $ 4.87 

Ether, 1 pint 80 

Fluor-spar, 1 pound .15 

Iron sulphate, 1 pound 05 

Lead acetate, 2 ounces .10 

" oxide, 8 ounces 10 

Litmus, 1 ounce .15 

Magnesium ribbon, 1 pwt 25 

Manganese, black oxide, 2 pounds ... .30 

Nitric acid, 5 pounds 75 

Nut-galls, 2 ounces .10 

Oxygen mixture, 3 pounds 1.20 

Phosphorus, 1 ounce .25 

Potassium, metallic, J ounce 1.00 

" bichromate, 1 pound .... .25 

" bromide, 4 ounces 40 

" carbonate, 1 pound .... .15 

" iodide, 2 ounces 80 

" hydrate, 1 pound .75 

" chlorate, 2 pounds 60 

" cyanide, 2 ounces .... .10 

" ferrocyanide, £ pound 25 

" nitrate, 1 pound .20 

" permanganate, 1 ounce 20 

" tartrate, 2 ounces . . . . .10 

Silver nitrate, 1 ounce 90 

Sodium, metallic, I ounce .50 

acetate, | pound 30 

bicarbonate, 1 pound .... .12 

carbonate, 1 pound 06 

hydrate .75 

chloride, coarse, 5-pound box . . . .10 
" fine, 3 pounds .... .09 

nitrate, 1 pound 25 

biborate, \ pound .10 

silicate, 1 pint 15 

sulphate, 1 pound .15 

Strontium nitrate, 4 ounces 10 

Sulphur-roll, 1 pound .06 

Amount carried forward ... $ 17.50 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 9 

Amount brought forward . . . $17.50 

Sulphur-flowers, 1 pound 10 

Sulphuric acid, 10 pounds .25 

Turpentine, spirits of, -J- pint 30 

Zinc chloride, 1 ounce .25 

Zinc, granulated. (See section 58.) 

Total $18.40 

Almost every manufactory of iron, woollen, or cotton 
goods uses sulphuric acid, where it can be purchased (as 
an accommodation) at the price quoted. Manufactories of 
woollen fabrics use chlorhydric and nitric acid. These 
acids, commercially pure, can often be obtained at such 
places much cheaper than of dealers in chemicals. Many 
of the chemicals will keep, unimpaired in quality, for an 
indefinite period. It is much cheaper to purchase such in 
bulk, and it is so directed in the above list. Keep all 
such chemicals in one and two quart fruit-jars. They are 
cheaper than regular salt-bottles, and, having wide mouths 
and tight covers, are equally good. Thus preserved the 
supply of many substances given will be sufficient to last 
for years. 

11. Cost of such a laboratory, fitted up for a class of 
twelve pupils in general chemistry, is : 

Hogshead and water-pipe $ 3.50 

Large table 25.00 

Lecture table 16.00 

Tank 5.30 

Storage closet 20.00 

Hood 2.50 

Apparatus and glassware 39.67 

Chemicals 18.40 

Total $130.37 

12. Laboratory No. 2. — This provides for the same num- 
ber of pupils as the first described, but is fitted up in a 



10 



ELEMENTARY CHEMICAL TECHNICS. 




Fig. 2. 

more complete and expensive manner, for work both in 
general chemistry and qualitative analysis 

It presupposes that the school building is supplied with 
gas and water, and provides only for bringing both into 
the room, and carrying the waste-water out 

13. Working Table. -Fig. 2 represents the table for 
the use of the pupils. It is made of white-wood, and 
stained, or of hard wood, and filled, and is of the same 

6 mXH aS g ; V6n - n Kg " L Each P U P° has a d ~> 
6 rnch.es deep, for private effects, and a locker, 22 inches 

high, for larger pieces of apparatus. 

J" *! le ' en <fosed spaces g g g, 1 foot in width, necessarily 
created by the set bowls, are placed earthen crocks to Z 
ceive solid matter that might clog the waste-pipes. 

The backs of these little recesses should be readily re- 
movable in order to give access to the interior of the table 
in case the plumbing gets out of order. 

On each side are three set bowls, nine inches in diameter, 
without stoppers, each conveniently placed for the use of 
two pupils. At e c c are gas-cocks furnished with straight 
tubes for supplying gas to the Bnnsen bnrners by means 
of f-mch rubber tubine 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 11 




f/G.3. 

DIMENSIONS. ft. m. 

Length 8 

Width 3 10 

Height 3 



14. Lecture Table. — Fig. 3 represents the lecture table. 
It is of white-wood, or hard wood stained or filled, and 
varnished. The top should only be treated to several coats 
of shellac. 

At a is a lead-lined water-tank, 30 x 18 inches in area, 
and 24 inches deep at one end. The other end should 
be but 3 inches deep for a distance of 12 inches. By this 
means bell-jars can be filled with water, inverted, and 
stand in shallow water. This is a much better arrange- 
ment than soldering cleats upon the sides of the tank and 
putting in slate shelves. Such shelves are pretty sure to 
break down at an unfortunate time. 

The table is supplied with water-cock, waste-pipe from 
the tank, and two gas-cocks for supplying fuel to two 
Bunsen burners. 

15. Storage Closet. — The plan is the same as described 
in section 7, but the closet is built of better stock, orna- 
mented with a cornice at the top, painted, has four glass 



12 



ELEMENTARY CHEMICAL TECHNICS. 



Height 




DIMENSIONS. 

FT. IN. FT. IN 



FIG. 4. 



doors instead of wooden ones, as in the cheaper closet, and 
is of larger dimensions, being 11 feet in length, 7 feet in 
height, and 1 foot 5 inches deep. 

16. Hood. — Fig. 4 represents a convenient hood. It 
consists of a chamber with bottom and two sides of wood. 
The remaining sides are window-sashes with four 11 x 11 
inch lights. One of the sashes is made to slide up and 
down as in an ordinary window. A dome-like roof of zinc 
is securely fitted upon the top of the chamber. The four 
sloping sides of this roof are narrowed until they reach a 
six-inch collar, over which is slipped a length of funnel 
which passes into a ventilator-box. The chamber is fas- 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 13 

tened, by means of large brackets, to the side of the room 
at a convenient height. Inside the chamber, upon one of 
the wooden sides, screw up a lamp-bracket to hold a large 
kerosene lamp. This should be kept constantly burning, 
while the hood is in use, to assure an ascending current. 
Remember that an upward draught cannot be secured with- 
out a corresponding inlet for cold air, and raise the sash a 
very little. If a ventilator-box is not available, carry the 
pipe of the hood out through a window, as directed in 
section 9. 

17. Plumbing. — The water-pipes should be so placed 
that every foot of them can be easily reached. Let the 
discharge pipes from the bowls be carried into a drain-tile 
main, and the latter must be securely trapped. Provide 
for shutting off the water supply and draining the pipes 
in cold weather. 

18. Equipments. 

Apparatus and Glassware. 

Beakers, 2 dozen 2|--ounce $ 3.60 

8 Bunsen burners, with ring 4.00 

6 mouth blowpipes . . . . . . 1.50 

1 hot-blast blowpipe, for working glass . . . 3.00 

1 book chemical tables .50 

6 dozen glass bottles, 4-ounce, ground stoppers . 8.10 

1 nest Hessian crucibles .30 

6 earthen crocks 72 

1 set of brass cork-borers 2.50 

6 test-tube brushes 72 

10 dozen corks, assorted sizes .... 1.20 
Cover glasses. (See preceding list of apparatus.) 

6 deflagrating spoons 1.20 

6 evaporating dishes, 3-inch 1.50 

1 pack of filter-paper, 6-inch .40 

3 files, round, fiat, three-cornered 60 

2 dozen 4-ounce flasks 2.40 

Amount carried forward ... $ 32.14 



14 



ELEMENTARY CHEMICAL TECHNICS. 



Amount brought forward . . . $32.14 

4 dozen 8-ounce flasks 85 

6 funnels, 3-inch 90 

2 pounds glass-tubing (assorted numbers) . . 1.00 

6 generators. (See section 31.) 

1 graduate, 4-ounce 40 

1 " English and Metric 90 

2 gas-bags, 55 gallons 25.00 

1 dozen gas-jars (use fruit-jars) .... 1.50 

1 dozen litmus-papers 40 

6 Wedgewood mortars, 3-inch .... 2.40 
6 nappies (large for pneumatic pans) . . . 2.10 

40 feet rubber-tubing, ^ 6.00 

Chemical scales 12.00 

6 iron retort-stands, 3 rings 5.00 

1 iron retort for making oxygen .... 3.00 
1 chemical thermometer . . . . . 2.25 
6 dozen test-tubes, 6-inch 2.16 

3 dozen " " 4-inch ..... 1.20 
Test-tube holders. (See section 36.) 

6 thistle-tubes .72 

3 U-tubes, 4-inch 75 

3 chloride of calcium tubes .90 

Tube for hydrogen tone 50 

Wash-bottles. (See section 43.) 

Brass wire gauze .50 

Iron " " (use mosquito-netting). 

Total $102.67 



Chemicals. 

Alcohol, 1 quart 

Arsenious acid, 2 ounces .... 
Alum, £ pound . ... 
Ammonia, 5-pint bottle .... 
Ammonium carbonate, 1 pound 

" chloride, " " . . 

nitrate, crystals, 1 pound . 

Aniline, red, | ounce 

Antimony (metallic), \ pound 

tartrate (Tartar emetic), 1 ounce 
Amount carried forward 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 15 

Amount brought forward . . . $2.90 

Barium hydrate, 1 ounce 25 

Barium sulphate, 1 " .10 

Benzole, 1 pint 30 

Bone-black, 1 pound .30 

Borax, 1 pound .20 

Bromine, 1 ounce .25 

Calcium chloride, 1 pound 40 

fluoride, 1 " 15 

" sulphate, 1 " 10 

Camphor, £ pound .25 

Carbolic acid, 1 ounce 15 

Carbon disulphide, 1 pound .50 

Cochineal, 2 ounces 10 

Copper trimmings, 1 pound .50 

" wire gauze 40 

Copper oxide, 1 ounce .20 

" sulphate, 2 pounds .24 

Chlorhydric acid, 5 pounds .35 

Ether, sulphuric, 1 pint 80 

Nut-galls, 1 ounce .05 

Gun-cotton, ± ounce 15 

Iodine, 1 ounce .50 

Iron sulphate, 1 pound 05 

Lead acetate, 2 ounces .10 

" carbonate, 1 pound 18 

" nitrate, 2 ounces .10 

" oxide, | pound 10 

Lithium carbonate, £ ounce .25 

Litmus, 1 ounce 10 

Magnesium, 1 pwt. (ribbon) .25 

" sulphate, 1 pound 10 

Manganese, black oxide, 3 pounds ... .45 

Mercury, 2 pounds 1.50 

" red oxide, 2 ounces .30 

Nitric acid, 5 pounds 75 

Nickel sulphate and ammonia, 2 ounces . . .40 

Oxygen mixture, 5 pounds 2.00 

Phosphorus, 1 ounce .25 

Amount carried forward . . . $ 21.62 



16 



ELEMENTARY CHEMICAL TECHNICS. 



Amount brought forward . . . $ 16.02 

Platinum foil, 1 pwt 60 

Platinum wire, 1 pwt .60 

Potassium, £ ounce 1.00 

" bromide, 2 ounces . . . . .20 

" bicarbonate, 1 pound 40 

" bichromate, 2 pounds .... .50 

" carbonate, 1 pound 20 

" hydrate, 1 pound .75 

" chlorate, 3 pounds 90 

" cyanide, ± pound .20 

" ferrocyanide, £ pound 25 

" iodide, 1 ounce .40 

" nitrate, 1 pound 20 

Potassium permanganate, 1 ounce ... .20 

Silver nitrate, 1 ounce 90 

Sodium, metallic, i ounce .50 

" acetate, £ pound 30 

" bicarbonate, 1 pound .12 

" carbonate, 1 pound 06 

" hydrate, 1 pound .75 

" chloride, 5-pound box 10 

" " (coarse fine) 3 pounds . . .09 

" nitrate, 1 pound 25 

" silicate, 1 pint .15 

" sulphate, 1 pound 15 

Strontium nitrate, | pound .20 

Sulphur-roll, 1 pound 06 

" flowers, 1 pound .10 

Sulphuric acid, 10 pounds 25 

Tinfoil (pure), \ pound .35 

Turpentine, 1 pint 60 

Zinc, chloride, 1 ounce .25 

Zinc, granulated, 4 pounds 1.20 

Total $28.80 



19. Cost of Laboratory No. 2. 

Plumbing 45.00 

Laboratory table 40.00 

Amount carried forward . . . $85.00 



CONSTRUCTION AND EQUIPMENT OF LABORATORIES. 17 

Amount brought forward . . . $85.00 

Lecture 23.00 

Tank 5.30 

Storage closet 45.00 

Hood 14.00 

Painting 20.00 

Apparatus and glassware 102.67 

Chemicals .... .... 28.80 

Total $323.77 

The list of chemicals is a general one, selected with a 
view to the use of no particular text-book. Of course the 
list can be modified to adapt it to any series of experiments 
a teacher may choose to have demonstrated. The prices 
of apparatus and chemicals quoted are many of them list 
prices. If purchases are made in considerable quantities, 
as is always advisable, from 10 to 15 per cent may be 
deducted in the estimates of the amount of the last two 
items. 

20. Labelling Chemicals. — All bottles and packages of 
chemicals should be labelled before they are placed in the 
storage closet. Books of printed labels, with structural 
formulas of the substance named, can be purchased, and 
are exceedingly convenient. In lieu of these, gummed 
labels 1\ x 1 inch may be purchased in small boxes. The 
names should be written accurately in ink. 



CHAPTEE II. 

GLASS- WORKING. 

21. A Supply of Soft Glass Tubing should be purchased 
by the pound and kept constantly on hand. 






Fig. 5. 

The sizes should run from one to eight. Sizes 3 and 4 
will be used more than others. Eubber tubing of the 
same calibre can be readily obtained, and tight but easily 
adjusted joints thus made. A small quantity of hard 
glass tubing, of sizes 2, 3, and 4, will also be required. 
Small tubing can be broken squarely at any point by 
scratching the glass at that point with a three-cornered 
file, and applying pressure against the opposite side of the 
tube from the scratch. The sharp broken edges should 
be removed by softening the end in the gas-flame or by 
grinding the ends of the tube in the manner described in 
Section 23. 

22. Boring Glass. — Holes large or small can be bored 
through the hardest glass, without any danger of cracking 
or shivering the glass, as follows : 

Dissolve gum-camphor in spirits of turpentine until a 
nearly saturated solution is obtained. Provide a number 

18 



GLASS- WORKING. 19 

of round files (new) of different sizes. Break off the tip 
of each file so as to riiake a sharp, ragged end. Select the 
smallest file. Dip the end in the turpentine solution, and, 
holding the file at an angle of about 45° with the surface 
of the glass, at the same time press the ragged tip against 
the glass and move the file rapidly to and fro. A depres- 
sion will immediately be made in the glass, and its thick- 
ness soon cut through. The teeth of the file can then be 
used. Keep the files constantly wet with the solution. 
Enlarge the orifice with files of successive sizes. Use files 
but a little smaller than the orifice itself. 

23. Grinding Glass. — Large surfaces of glass can be cut 
away and ground very rapidly, and without any danger of 
breaking, by using flat files constantly wet in the turpen- 
tine solution." If accurate grinding of plane surfaces is 
required, another device is necessary. Bell-jars may be 
made to fit the pump-plate, or pneumatic jars squared off 
for use with cover-glasses, on a lathe. Prepare a disk of 
hard wood 1£ inches in thickness, and with a diameter con^ 
siderably larger than that of the largest jar to be ground. 
]\felt together pitch, tallow, and glue in the proportion of 
10 parts of the first, 2 of the second, and 5 of the last, and 
stir into the fluid just before it cools (not too soon, or it 
will settle irregularly through the mass) a large quantity 
of medium fine emery. Coat the face of the disk thickly 
with this mixture while it is hot enough to spread easily. 
In a few hours the disk will have a good grinding surface. 
Attach this improvised emery-wheel to the shaft of the 
lathe, or even upon a common whirling-table. Keep the 
surface wet with the turpentine solution. Hold the jar 
firmly and squarely against the revolving disk. 

24. Cutting Glass. — Plane surfaces of glass can be cut in 
straight lines or curves ; large tubing, necks and bottoms 
of bottles cut off very easily and rapidly by taking ad van- 



20 ELEMENTARY CHEMICAL TECHNICS. 

tage of the expansion of glass when heated. The disks of 
hardened steel made for cutting glass often work well for 
a short time, but are liable to give out suddenly. Good 
diamonds are expensive, easily broken, will cut well only 
in straight lines, and always leave a sharp cutting-edge. 
None of the objections are to be met with in using heat. 
The tools are very simple and inexpensive. Procure two 
rods of soft iron (not steel) from § to % inch in diameter, 
one 12, the other 15 inches in length. The best possible 
material is the soft iron rod, used to fasten together the 
parts of a stove, obtainable at any stove store. The shorter 
one should be perfectly straight. Bend the longer one in 
a somewhat sharp compound curve. Insert them in wooden 
handles which can be purchased at a hardware store. To 
cut a plane surface, as a window-pane, heat the straight 
rod, if the glass is quite thick (J inch or more), to a 
red heat; if thinner, not so hot. Then with a three-cor- 
nered file, wet with the turpentine solution, cut a deep 
groove in the edge of the glass and place the glass upon 
the even surface of a table. Place the heated rod flat 
upon the glass, with the end ^ f an inch below the file- 
mark. Now draw the rod downward in the direction in 
which you wish the cut to run, and the crack will follow 
if you keep the rod about £ of an inch ahead of it. If the 
rod is very hot, be careful that the crack does not quite 
catch up. If it does, it may dart on and take a direction 
of its own. With a camel's-hair brush dipped in black 
paint, or with pen and ink, mark out any design in circles 
or scallops, curves or straight lines. A little practice will 
enable one to cut the glass by these lines with perfect 
accuracy, and the edges will be much smoother than when 
cut with a diamond. 

25. To cut open Large Tubing, bottles, etc., heat the 
curved rod. With the file, wet as before, cut a groove from 



GLASS-WORKING. 21 

\ to £ inch in length, according to the size of the tubing 
or bottle, and nearly through the thickness of the glass. 
Wipe off the turpentine solution from the vicinity of the 
groove. Place the heated rod first against the end of 
the groove in the position a in the figure, and wait until 
the glass is heard to crack. Then press it against the 
other end of the groove in the position b, and the crack 
will start and follow the rod round the bottle in the 
direction indicated by the arrow. 




F/G. 6. 

26. To bend Tubing. — To bend large tubing pack it full 
of fine sand, and heat it in a charcoal or bituminous-coal 
fire. Get a blacksmith to accommodate you with his forge 
fire. 

For bending small tubing do not use a Bunsen burner 
or alcohol lamp. The best possible flame is obtained by 
removing the tube of a Bunsen burner and screwing on in 
its place a fish-tail burner. Hold the tube lengthwise in 
the flame, constantly turning it. The moment when it is 
soft enough to bend is judged better by the feeling, as it 
turns in the fingers, than by the eye. To prevent its flatten- 



22 ELEMENTARY CHEMICAL TECHNICS. 

ing, bend it about 30° in one direction, then remove it from 
the flame and bend it slowly to the required angle in 
exactly the opposite direction. If a gas-flame cannot be 
had, use the flame of a common kerosene lamp, or, better, 
lantern. The deposit of carbon is easily wiped off with a 
piece of flannel while the tube is warm. 

27. To Etch Graduations upon Eudiometers, etc. — Be 
sure the tube to be marked is perfectly clean. If not, 
wash it with strong soap-suds. Then cover it with a thin 
coat of paraffine. This may be done by rubbing the heated 
tube with a paraffine candle. The thinner the coat, to 
completely cover the surface, the better. The graduations 
may be of inches or centimeters. If the latter is desired, 
excellent finely divided scales may be obtained of any 
agent of the Metric Bureau. Place the tube and yard- 
stick, or whatever scale is used, together horizontally upon 
a table, blocking up the latter so that the surfaces of the 
tube and scale are exactly level. Then with a carpenter's 
try-square, set squarely against the side of the yard-stick, 
you can make the markings on the glass exactly correspond 
with the divisions of the scale. Mark completely through 
the wax with a sharp-pointed needle. Place figures at 
the inch or centimeter divisions. In a leaden pan, or a 
piece of sheet-lead folded into a sort of pan 3 or 4 inches 
square, mix up a thin paste of calcium flouride and strong 
sulphuric acid (a table-spoonful of the former will be 
enough), and arrange the tube, with marked side down, 
horizontally over the lead pan. Fold a large piece of 
stout paper over the tube, so as to completely shut in the 
tube and pan. Gently warm the pan for 3 or 4 minutes. 
The heat must be very moderate, so as not to melt the 
wax. Remove the heat, and let the apparatus stand several 
hours, — all night, if convenient. Do this work under a 
hood or in a strong draught, for the fumes are very corro- 



GLASS-WORKING. 23 

sive to the lungs. Finally, remove the wax and clean the 
tube with spirits of turpentine. 

28. To Close Tubes. — Mark off upon a long piece of 
tubing the length of the required tube. Heat the tubing 
at that point, constantly revolving it in the flame. When 
it is soft enough, suddenly, and in a direct line, draw it 
out till the bore is closed and the tube parts. Then heat 
the end to be closed again till the glass becomes plastic, 
and with the heated handle of an iron spoon press the 
tapering end back, and round it into shape. If the end 
to be closed is not attached to a long rod, first heat the 
end till it is soft, then while it is still in the flame press 
another piece of soft tubing against it till the two are 
welded. The second piece will then constitute a handle 
by which the tube can be drawn out and then closed. 



CHAPTER III. 

CONSTRUCTION OF APPARATUS. 

29. Some pieces of apparatus it is highest economy to 
purchase, made of the best materials and in the best man- 
ner. On the other hand, the list of essentials for the outfit 
of a chemical laboratory that can be made by the ingenious 
teacher or pupil, or furnished from home to the wonderful 
lessening of bills of expenditure, is a very long one. Let 
it be a rule that pieces of apparatus made for a special 
purpose, after using, shall be put away clean, in a case, 
and sacredly kept for that purpose. It is poorest economy 
not to furnish materials enough to obviate the make-shift 
necessity of pulling a piece of apparatus apart to obtain 
the tubing and other portions to supply a present need. 
Let everything be prepared in advance of the time for its 
use. A cork bored or fitted to a bottle in a hurry is almost 
sure to leak. 

Every piece of apparatus described in this chapter will 
meet the requirements for which it is intended, 
|r~ ' if well made. 
JSL 30. Aspirators. — Fig. 6 is an aspirator made 

from a two-quart pickle-jar. The larger the 
bottle the better for many purposes, a is an 
inlet tube of No. 4 tubing 6 inches long. At b 
a hole i of an inch in diameter is drilled, and 

Fig. 6. 

the orifice closed with a cork. 
To use it, fill the jar with water by opening b, and 

24 



CONSTRUCTION OF APPARATUS. 



25 



Id 



c 




holding the jar under water till full. Then connect a by- 
rubber tubing with the vessel through which a draught is 
desired, and let the water run into a vessel prepared for 
its reception. 

A small aspirator of this kind should be prepared, of a 
half-pint capacity, or less, for use in some experiments, 
as withdrawing gas from candle-flame (Section 129, b). In 
experiments requiring a steady and uninterrupted draught 
for some time this aspirator is unsatisfactory. For such 
purposes make the following: 

Fig. 7 is a tin tube f of an inch in diameter and 36 
inches long, a is an inlet tube a trifle smaller, 3 inches 
long, inserted 8 inches below the tunnel b. d is a rubber 
supply pipe connected with a water-cock. 

To use, connect a with the vessel through which the 
draught is to be made, and turn on the water at d. The 
dimensions given are not essential, but the tube must be 
small enough for the supply of water to keep the neck 
of the tunnel b constantly full, and a should be of the 
right size to slip the rubber tubing over. 



26 ELEMENTARY CHEMICAL TECHNICS. 

Fig. 8 has an arrangement for making a draught by using 
a or of obtaining an air-blast by connecting with e. c is 
a piece of sheet-cork 2\ by 2 by 2£- inches, dipped in 
melted paraffine to fill its pores, b is a glass tunnel and 
/ No. 3 glass tubing, s is a siphon for withdrawing the 
water. Regulate the length of s, so that it shall not 
remove the water certainly any faster than it comes in. 
If a water supply is not at hand, a can be used to good 
advantage, and even e to some purpose, by steadily pouring 
water into b from a large pitcher or nosed tin-pail. 

Fig. 9 represents a convenient piece of apparatus for 
obtaining a draught through a liquid, a is a piece of glass 
tubing one inch in diameter, and 8 or 9 
JL s)=^* o ) -£ inches long. The top of an argand 
\ d lamp-chimney is suitable. The ends are 

closed with corks glued in. b is a piece 
of No. 3 glass tubing 6 inches long; c is a piece of No. 
2 of the same, drawn to a fine jet-point. This tube must 
be fitted to the cork loosely enough to allow of its being 
drawn back and forth for adjustment. At d the tube is 
bored for the admission of a cork, through which is passed 
a straight piece of No. 4 tubing 3 inches in length. A 
steady blast from the mouth through c will produce as 
good draught through d, which can be connected with any 
piece of apparatus through which a draught is desired. 
When convenient, connect c by rubber tubing with the 
air-cock of a steam radiator. 

31. Gas Generators. — A supply of generators for H, N 0, 
H 2 S, etc., should be kept constantly on hand, fitted up 
as shown in Fig. 21. Select horse-radish bottles with per- 
fectly circular mouths and lips not nicked out. The corks 
must fit the bottles nicely, and the tubes the holes in the 
corks. To ascertain if all joints are tight, close the mouth 
of the delivery tube, and blow through the thistle-tube. 



& 



CONSTRUCTION OF APPARATUS. 27 

Fig. 10 represents a self-regulating generator for H 
very convenient when only a small quantity of gas is 
needed at a time, a is a pickle-jar, b is an 
olive-oil bottle with the bottom cut off, and & 

the neck passed through the cork of the jar. JET 
The neck of the bottle is fitted with a cork -/nR 
and delivery tube, c is a piece of rubber 
tubing 6 inches long; d is a pinch-cock de- 
scribed below. At e is a little wire basket 
made of a circular piece of wire netting no JO. 
folded up at the edges and filled with granu- 
lated zinc. To use the apparatus, remove everything from 
the jar and nearly fill it with a mixture of H CI and water, 
1 part to 8, or H 2 S 4 , and water 1 part to 12. Then open 
d and slowly lower b into place. Close d ; gas will be gen- 
erated in b, and expel the liquid. When the acid is driven 
below the basket of zinc, action will cease. Upon drawing 
out the gas the liquid will be readmitted and more gas gen- 
erated. The first bottleful of gas will be unfit for use. Let 
the large cork fit the bottle loosely, or bore a hole in it. 

32. Gas-holders. — The aspirator, Fig. 6, can be used 
for a gas-holder. Fill it with water. Connect a with the 
gas-generator, and let out the water, regulating its exit by 
the rate at which the gas is generated. This can easily be 
done, in the case of H, by watching the end of the thistle- 
tube under the liquid. 

Large hog's or beef's bladders make excellent gas-holders. 
Inflate the fresh bladder. After it is dry, smear the 
outside with sweet-oil, to which has been added a few 
drops of carbolic acid; place a little oil inside, and work 
the bladder thoroughly in the hands. This will prevent 
any drying, cracking, or offensive odor. Next insert a piece 
of glass tubing into the neck, and wind it very securely 
with linen thread. Slip over the end of the tubing a 



28 ELEMENTAEY CHEMICAL TECHNICS. 

piece of rubber tubing, a few inches long, upon which is 
placed a pinch-cock, represented in Fig. 11. 

33. Gas-cock. — Obtain of a harness-maker or hardware- 
dealer the clasp made to slip on a horse's rope- 
halter. Place over the end of the screw b the top 
of a rubber eraser from the end of a lead-pencil. 
This when placed upon rubber tubing makes a 
tight gas-cock and regulator. (Without the rubber, 

Fig. 11 shows a convenient screw-clamp for bat- 
tery wires.) 

34. Large Receptacles for Gas. — Altogether the most 
satisfactory gas-holders are rubber bags, made wedge-shaped, 
and fitted with a well-packed cock. Two surfaces of inch 
board of the same shape, and with each dimension a little 
larger than the upper and under surfaces of the bags, 
should be furnished. Fasten the edges of the boards 
corresponding to the front end of the bag together with 
strong iron butts. Saw out from the edges a square open- 
ing large enough to pass the brass cock through. Then 
fold these wooden platforms and shut the bags between 
the surfaces, and draw the cock through the opening. 
After filling the bag, place heavy weights of stone or 
sand upon the upper boards. These can be kept in place 
by cleats nailed to the upper sloping surface. Make it 
a rule never to remove a weight while the issuing gas is 
connected with a burning jet. The relief of pressure may 
cause a mixture of gases to be resorbed and an explosion 
follow. If this precaution is observed, rubber bags are 
perfectly safe. Two bags of a capacity of 56 gallons fitted 
with gas-cocks may be bought for $ 25.00, and smaller ones 
at proportionate prices. 

But these expensive rubber bags are not at all necessary 
for a school, unless it is desired to produce the calcium 
light. 



CONSTRUCTION AND APPARATUS. 



29 




Fig. 12 represents a very cheap and convenient gas- 
holder, a and b are tin paint-cans discarded in great 
numbers at every paint-shop. The diam- 
eter of b is a little less than that of a. . A » -^ *, 

A wooden keg, with one head knocked 
out, answers well for a. c is a piece of 
glass tubing, bent as shown in the figure, 
and passed through a cork at d, which is 
fitted to a hole in the tin or wood at that 
point. A wire loop is soldered to b at e, 
and at / and / tin sockets are soldered 
or riveted to receive the wooden uprights 
g g. The pulleys h h can r5e obtained of f/G. /£. 

a hardware-dealer, a is filled with water, 
and nearly counterpoised by k, a baking-powder can fur- 
nished with a wire bail and filled with sand. The inner 
end of the tube c should rise a very little above the edge 
of the tank a to insure against the entrance of any water. 
On the outer end of c is placed a piece of rubber tubing 
with a pinch-cock. To fill the holder, remove k, open the 
pinch-cock and press down the receiver b till it is filled 
with water. Then hang on k again and connect the de- 
livery tube c with the generator. 

If desired, a tinman will make a and b of zinc of any 
required size. Make b 18 inches in diameter and 36 inches 
high, and it will hold about 40 gallons of gas. a should be 
38 inches in height and 20 inches diameter. There should 
be sockets for the uprights soldered on both top and bottom 
of <z; and c should be so placed as to issue from a at a 
point 90° from / and / instead of at the point shown in 
the figure. Let the wooden frame be of inch-pine stock 1J 
inches wide with the cross-bar mortised upon the uprights 
g g. If the receiver is well coated with paint it will hold 
O or C 2 any length of time, but H will leak out in a very 



30 



ELEMENTAEY CHEMICAL TECHNICS. 




Fig J 3. 



few hours. Gas cannot be subjected to great pressure in 
these, on account of the overflowing of the water. The cost 
of a 40-gallon gas-holder of this description is $ 5.00. 

35. Pipette-stand. — Fig. 13 represents a pipette-stand, 
useful for holding test-tubes, flasks, and small retorts while 
heating. The base of the stand is a broad, low bottle filled 
with sand, and the standard a piece of No. 3 glass tubing, 
18 inches long; b is a piece of sheet-cork in dimensions 
2J x 2 x 1£ inches, c a piece of hard wood 15 inches in 
length. From c to d it is \ of an inch thick, 1J- inches 
wide, and 8 in length. From d to / it is turned into a 
smooth rod, of the diameter of No. 3 glass tubing, g is 
another piece of hard wood of the same width and thick- 
ness of c, 7 inches in length, fastened to c f at h with 
a brass butt, r is a stout band of rubber. It is well to 
glue in thin pieces of cork flush with the inner surface 



GENERAL MANIPULATIONS. 31 

just where the necks of flasks will touch the wood. If 
the holes in b are not made too large the friction of cork 
and glass and wooden rods will be sufficient to retain the 
holder at any height and any angle. 

36. Test-tube Holders. — Prepare strips of hard wood 1£ 
inches wide, £ inch thick, and 8 inches long. One inch 
from the ends hollow out the inner surface to 
fit the circumference of a test-tube. Glue into 
these hollows pieces of asbestos-packing. Fasten 
the other ends of the pieces together with brass f/6./4. 
butts and pass a strong rubber band around them. 

37. Iron Stand for Heating. — Bend 4 pieces of annealed 
wire of the size of telegraph-wire, 16 inches in length, in 
the shape represented in Fig. 14, so that the horizontal 
part shall be 6 inches long, and the uprights 4. Bind the 
uprights together by winding them with small copper-wire 
in such a way as to make a square-topped stand. Make 
the stand more stable by setting a large cork squarely 
upon the end of each leg. Cut out of wire-netting a 
square 6 inches upon a side and place it upon the top of 
the stand. 

38. Tubulated Gas-jars. — (See Fig. 15.) These take the 
place of expensive bell-jars with stop-cocks, for two pur- 
poses, — for collecting gases over water and 

JL<* transferring to other vessels and gas-bags, and 
_P^ for collecting and testing combustible gases, as 
acetylene, etc. 

For the first mentioned purpose select a large 

narrow-mouthed bottle, the larger the better, and 

cut off the bottom. (See Sec. 25.) Through the 

cork, closing the mouth, pass one of the metallic- 

F/G./5. capped stoppers used in tooth-powder bottles, 

which can be bought of any druggist for four cents. Settle 

the cork below the rim of the bottle and fill the hollow 



32 ELEMENTARY CHEMICAL TECHNICS. 

with, melted sealing-wax. To transfer gases with this, press 
the cap c firmly npon the tube and collect the jar full of 
gas over water in the ordinary way. Lift upon the jar just 
enough to counterbalance its weight, slip off the cap and 
put in its place the end of a rubber delivery tube. Then 
sink the jar deep in the water of the pneumatic tank. 

39. Sand-baths. — Obtain of a stove-dealer pieces of sheet- 
iron 7 inches square. Have a square inch cut out of each 
corner, and bend up a rim an inch deep on each side. If 
a tight joining is not secured at the corners, fold in pieces 
of asbestos-packing. Use clean beach-sand, a shallow layer. 

40. Water-baths. — Cover the top of a rolled tin basin, 
of a half -pint capacity, with wire-netting (mosquito-bar), 

securing it firmly by a wire bound around under 
the rim of the basin. Cut a large circular open- 
ing in the netting, of such a size that the evapo- 
rating-pan will settle through it two-thirds of 
Fig. 16. its depth. Cut another circular opening at one 
side to receive the neck of a tall bottle. Fill the 
basin to such a height with water that the bottom of the 
evaporating-pan shall be submerged. Then fill the bottle 
with water and invert it in the basin through the opening 
made for its reception in the netting. This bottle will 
keep the depth of the water constant and save the necessity 
of continual watching. 

41. Cork-borers. — As sets of brass cork-borers are quite 
expensive, substitutes may be provided. Make cylinders 
of tin 7 inches in length, and of the sizes of glass tubing 
from 1 to 5. Provide a stout piece of wire of the same 
length as the tubes, which will be of use to punch out the 
pieces of cork from the borers, and by cutting holes 1 inch 
from the top end of the larger borers and passing the wire 
through horizontally, it becomes a very useful handle in 
boring large corks. Keep the outer circumference of the 
tubes filed to a sharp edge. 




GENERAL MANIPULATIONS. 33 

42. Deflagrating-spoons. — Make a hollow in the top of 
an ordinary school-crayon. Break off an inch of the crayon, 
and a little above the middle of this piece wind the end of 
a piece of copper wire 12 or 15 inches long. This can be 
bent at any angle for a handle. 

43. Wash-bottles. — Fig. 18 (part marked b) represents 
a convenient arrangement for washing 0, H, and other 
gases. It is made of a wide-monthed quart bottle. The 
inlet tube reaches to the bottom of the bottle ; the delivery 
tube b passes only through the stopper. It is well to sink 
the cork deep and pour in melted wax (see Sect. 58) over 
the top. In that case the bottle can be filled by attach- 
ing a long rubber tube to the exit tube I, placing the end 
of the rubber tube in a pail of water, holding the bottle 
below the level of the water, and sucking out a little air at 
the inlet k. To clean out the bottle the water can be 
ejected through the inlet k by blowing into the exit I. By 
introducing H 2 S 4 into the bottle the same piece of appa- 
ratus can be used for drying certain gases. A small hole 
drilled in the side of the bottle near the bottom is useful 
in filling the bottle and rinsing after using. It can be 
securely closed by means of a phial cork. 

44. Drying-tubes. — They should be made of tubing at 
least an inch in diameter. If tubing so large is not at 
hand argand lamp-chimneys, either with the larger base 
cut off or remaining on, are excellent. If desired, soft 
tubing may be bent into U-tubes (see Sect. 26). But for 
most purposes straight tubes about 10 inches in length 
are very convenient. Fit corks securely to the ends, and 
pass through each cork pieces of No. 3 glass tubing, 2-|- 
inches long. Fit to the end of each tube a piece of rubber 
tubing 2 inches long, into which glass stoppers can be 
thrust to seal the tube when charged with calcium chloride, 
and not in use. 



34 ELEMENTARY CHEMICAL TECHNICS. 

45. Cheap Alcohol Lamps. — Make them of wide-based 
mucilage or ink bottles. Fit sound corks to the necks of 
the bottles, and bore a little hole in the corks for a vent. 
Cut off two inches from a tin pea-shooter and pass it 
through the cork vertically. Fill this tube with strands 
of candle-wicking. Use spent copper pistol-cartridges for 
caps for the lamps. 

46. Blowpipes. — Use No. 3 glass tubing. Cut off pieces 
8 inches long. Two inches from an end bend the tube care- 
fully at right angles, and draw the nearer end to a fine jet- 
point. 






CHAPTEK IV. 

GENERAL MANIPULATIONS. 

47. To collect Gases. — Gases may be collected in a pure 
state in large jars, by causing them to displace the sub- 
stance already occupying the jar. What this substance 
should be depends upon the properties of the gas to be 
collected. 

Gases insoluble in cold water, as oxygen, hydrogen, 
nitrogen, nitrous oxide, nitric oxide, carbonic oxide, and 
many of the hydrocarbon gases, may be collected in the 
pneumatic tank by displacement of water. Fill the gas- 
jars completely with water. Place a cover-glass (made of 
common window-glass cut in squares a little larger than 
the diameters of the mouths of the bottles) over the mouth, 
and holding the cover-glass in position, with the fingers 
of one hand quickly invert the bottle without spilling any 
of the contents, and stand the inverted jar, with the mouth 
under water upon the shelf of the pneumatic tank or in the 
large earthen pneumatic pans containing two or three inches 
of water. Slip out the cover-glass and place three large 
iron nuts under the rim of the bottle's mouth in such a 
way as to support the bottle firmly. (A still better way is, 
as directed in many text-books, to file out of the rim of a 
flower-pot saucer a notch sufficiently large to pass the de- 
livery tube through, and place the saucer wrong side up in 
the tank. Then set the jar centrally over the hole in the 
bottom of the saucer and push the delivery tube under it 

35 



36 ELEMENTARY CHEMICAL TECHNICS. 

through the notch.) The delivery tube of the generating 
flask can then be passed under the bottles and the gas 
allowed to bubble up. When the jar is full of the gas, 
slip the delivery tube under the mouth of another bottle 
similarly prepared. Then insert the cover-glass under the 
mouth of the first bottle and set it upright upon the table. 
If the gas is not to be used for some time, it is well to 
smear the rim of the bottle with soft tallow before filling 
it, and then to press the cover-glass down firmly before 
leaving it. 

Most gases soluble in water may be collected by displace- 
ment of mercury or air. As the former is expensive, and 
from its great weight involves difficulties, it is not a con- 
venient medium for use. Gases lighter than air, as ammo- 
nia, chlorhydric acid-gas, etc., are collected by downward 
displacement of air. Hold the gas-bottle in an inverted 
position and pass the delivery tube upward to the bottom of 
the bottle. 

Gases heavier than air, carbon dioxide, etc., are collected 
by upward displacement of air. Place the gas-jar mouth 
upward upon the table and pass the delivery tube down to 
the bottom of the bottle. 

Neither water nor mercury can be used in collecting 
chlorine, for it is soluble in the one and corrodes the other. 
Use hot water or strong brine, or collect it by upward dis- 
placement of air. 

48. Transferring Gases from one Vessel to Another. — 
Hold the jars with their mouths under water in the pneu- 
matic tank. Insert the mouth of the vessel containing the 
gas under that of the one to receive it, which must be full 
of water. Then decant the first jar downward till the gas 
bubbles up into the second. 

49. Two Difficulties Present Themselves in Collecting 
Gas over Water. — The pressure of the water upon the 



GENERAL MANIPULATIONS. 37 

mouth of the delivery tube causes the generator to leak, 
and the water is liable to be resorbed into the generating 
flask, when heat is employed in generating the gas. 

After making the joints of the generator as tight as 
possible, the first trouble may be obviated by keeping the 
depth of water in the pneumatic pan as slight as possible, 
and sometimes by passing the delivery tube, at first, upward 
a considerable distance into the inverted jar. 

The danger of resorption is much less when liquids than 
when dry solids are heated ; and this liability can be wholly 
averted in heating liquids by passing a thistle tube through 
the cork of the flask, the end just dipping under the liquid. 
With this protection, sometimes called a " safety tube," if 
a partial vacuum occurs, air, and not water, will enter and 
fill it. In heating dry substances in a glass flask, as in 
fact in heating anything while the mouth of the delivery 
tube is under water, adopt the rule never to slacken the heat 
without first removing the tube from the water and shaking 
it free from adherent drops. 

If by any accident cold water is forced back into the hot 
flask, an explosion is pretty certain to result. 

50. To Heat Glass Vessels without Danger of Cracking 
Them. — If a strong heat is needed fasten the flask securely 
in the retort-stand at an angle of 45° or 50°, and holding the 
lamp in the hand, first heat the upper part of the flask, 
then the lower, gently moving the flame to and fro over 
every part of the glass so that the expansion may be uni- 
form. Do not let the flame play suddenly and violently 
upon one part. A square of wire-netting placed on the 
ring of the retort-stand under a heating flask or a sand- 
bath distributes the heat and greatly lessens the danger of 
breaking. 

51. To Bore Corks and Fit Tubing. — Select a borer a 
trifle smaller than the tube to be inserted, and if necessary 



38 ELEMENTARY CHEMICAL TECHNICS. 

enlarge the hole a very little with a round file. Always 
bore through from the under surface of the cork. Tarr. 
the glass tube into the cork; don't push it. Work with 
the fingers close down to the cork. If the friction is likely 
to be considerable, rub the tube with a piece of tallow. It 
is not advisable to use hard soap for this purpose, as it 
sets the tube immovably in the cork. Eubber corks may 
be bored readily by keeping the borer constantly wet with 
water. 

52. To Evaporate Solutions. — If it is desired to obtain 
crystalline salt from a solution, the more slowly the process 
is carried on the larger and more perfect will be the crys- 
tals. Use a gentle heat, keeping the temperature of the 
liquid just below boiling. The flame of an alcohol lamp 
can be reduced by picking the wick down; of a Bunsen 
lamp, by partially shutting off the gas. If this causes the 
flame to snap out or descend and burn at the base, bind a 
cap of fine wire-gauze over the top of the tube. Filter solu- 
tions before evaporating. 

53. To Filter. — Packages of filter-paper, circular in 
shape, adapted to the size of the glass funnels to be used, 
6 inch paper for 3 inch funnels, should be purchased. 
Told one of these circular sheets exactly in the middle, the 
crease marking a diameter, and the curved edge of the two 
halves laid together. Then fold this in the middle again, 
making the sheet J the original size. Now open one of the 
folds so that three thicknesses come upon one side and one 
upon the other, and you have an inverted cone which will 
just fit into the funnel. Insert the cone and place the fun- 
nel in a small ring of the retort-stand. 1 Then pour in the 
liquid to be filtered and place underneath a beaker in such 
a way that the lower end of the funnel shall rest against 

1 Tallow rubbed upon the under side of the lip of beakers will prevent liquids 
from running down the outside in pouring. 



GENERAL MANIPULATIONS. 39 

the side of the beaker. If enough liquid is quickly poured 
in to nearly till the funnel there is danger that some will 
work down between the paper and the glass. Avoid this 
by pouring a little liquid at a time down the surface of a 
glass rod held in nearly a vertical position with the end 
resting in the apex of the tunnel. 

54. To Dilute Acids. — Water is miscible with the com- 
mon acids in any proportion. In diluting pour the speci- 
fically heavier acid into the lighter water, not the water 
into the acid, and stir the mixture as you pour. This pre- 
caution must never be forgotten in mixing sulphuric acid 
and water. 

55. To Remove Glass Stoppers. — If glass stoppers be- 
come fast in bottles, wrap a "bandage" of cloth wet in 
hot water around the neck. This must not be done with 
bottles containing ammonia or ether. Instead, draw a line 
of oil or glycerine around the edge of the stopper in the 
neck, and leave in a warm place for a few hours. 

56. To Dry Gases. — Various methods are in use for this 
purpose. Allow the gas to bubble through a little strong 
H 2 S 4 in a wash-bottle, or fill a wash-bottle with lumps of 
pumice-stone wet in the acid. Another method is to pass 
the gas through straight tubes or bent tubes, filled loosely 
with calcium chloride or quicklime. Of the three sub- 
stances mentioned use in each case the one which has least 
affinity for the gas to be dried. H 2 S 4 will soon absorb 
enough moisture to increase its bulk considerably, and 
should then be rejected for the purpose. Calcium chloride 
and oxide can be used several times, if the precaution is 
taken to plug the openings air-tight after using. 

57. To Solder. — Three conditions must be fulfilled in 
order for success in soldering. The soldering-iron must be 
well u tinned." The surface to be soldered must be per- 
fectly clean, and the novice must exercise a little patient 
practice in the art. 



40 ELEMENTARY CHEMICAL TECHNICS. 

Purchase an " iron" of at least a pound's weight. With 
a flat file square off the faces at the point, smooth and 
bright, and file the sides of the iron bright and clean. Set 
the iron heating, and select a common brick with a slight 
depression near the middle of one of its large faces. 
Sprinkle powdered rosin abundantly into the hollow in 
the brick. When the iron is just below a red heat, holding 
a bar of solder over the brick, with the hot iron melt off a 
quantity, letting it drop upon the rosin. Then rub the 
iron vigorously against the surface of the brick through 
the globule of molten solder till a bright "tinned" surface 
appears upon the iron. In this way coat thoroughly each 
of the pyramidal faces at the point, and a little area back 
of each face. Occasionally renew this "tinning" as it 
becomes burnt off. 

The solder may be made to adhere to new tin by merely 
wiping it with a cloth and sprinkling fine rosin over it. 
The surface of old tin must be treated with " solder fluid." 
Prepare this by dissolving an ounce of granulated zinc in 
about two fluid ounces of hydrochloric acid, adding the 
zinc in small successive portions, to prevent the fluid from 
frothing over. Do this under the hood or out of doors. 
A desk mucilage-bottle is convenient to keep this fluid in, 
and the brush belonging to such a bottle is just adapted 
for applying the fluid to the surface to be soldered. This 
chloride solution is corrosive to the surface and must be 
cleaned off scrupulously after the soldering is done. Have 
a large piece of woollen cloth or cotton-waste wet with 
acidulated water to wipe the hot iron upon before apply- 
ing it to the solder. Melt off the solder from the bar in 
small quantities at a time and draw the iron slowly over 
the surface to be covered. 

58. To prepare various Substances needed in the Lab- 
oratory. Lime-water. — Place a lump of quicklime, 3 inches 



GENERAL MANIPULATIONS. 41 

in diameter, in a tall jar containing two quarts of water. 
Leave it over night. In the morning stir up the sediment. 
This will form "milk of lime," useful in some experiments. 
Allow the lime to settle. Then draw off the clear liquid 
with a siphon. Filtration is not necessary if the sediment 
is not disturbed at all while drawing off the liquid. If the 
water is not perfectly clear it should be filtered. 

Baryta Water. — Purchase barium hydrate and prepare 
the water in the same manner as lime-water. 

Litmus Solution and Paper. — Boil litmus in water till 
a strong decoction is obtained. To one portion add a few 
drops of caustic potash solution, for blue litmus, and to 
the other a few drops of dilute hydrochloric or acetic acid 
to make the red. These solutions are useful as long as 
they can be kept without fermentation. Strips of unsized 
papers, dipped in the liquids and dried, make very con- 
venient test-papers. Keep these in a wide-mouthed, stop- 
pered bottle. 

Purple Cabbage Solution. — Select a small cabbage of 
deep color. Chop it into fine pieces and place in cold 
water. Let the mass simmer for at least an hour over 
moderate heat, then boil vigorously for a few minutes and 
strain off the liquid. The solution may be kept unferment- 
ed a long time by putting it up in bottles, hot, and sealing 
the corks with wax. Do not put in alcohol as a preser- 
vative. 

Wax for Sealing Bottles, etc. — Melt together 10 parts 
by weight of pitch, 10 of gum-shellac, and 4 of beeswax. 
Add the shellac after the pitch and wax are completely 
melted, and stir until the whole mass is fluid. Then cast 
into sticks of convenient size. Prepare moulds for casting 
the sticks by filling a bucket with fine, moist sand, pressing 
it in hard. Make the holes for the casts with a long pencil 
or square wooden rod of the desired size and shapes. 



42 ELEMENTARY CHEMICAL TECHNICS. 

Granulated Zinc- — Break or cut into pieces of conven- 
ient size, to be contained in an iron ladle or large Hessian 
crucible, a quantity of sheet zinc or spelter. Melt the zinc 
over a coal fire. With an iron spoon skim off the dross, 
and pour the molten metal slowly in a fine stream from a 
height of four or five feet into a pail of water. 

59. Accidents and Emergencies in the Laboratory. — 
It is the duty of teachers to take every precaution with 
regard to the health, safety, and comfort of pupils working 
in a chemical laboratory. But foresight and watchfulness 
cannot forestall all accidents among a large number of 
young and inexperienced workers. 

Burning Clothes and Person. — Every pupil should wear 
a large, strong apron of some pattern in the laboratory. 
Many teachers forbid the use of aprons of cotton goods on 
account of the ready inflammability of the material. The 
hot nonluminous and inconspicuous flames of the Bunsen 
and alcohol lamps are a constant menace to the clothing 
of careless pupils. Therefore recommend, if not enforce, 
the wearing of aprons of some cheap strong, woollen 
material. Keep a large old overcoat or woollen blanket 
hanging in the room. This wrapped closely and promptly 
about burning clothes will usually quench the fire without 
serious results. It is much more effective, and certainly 
preferable to dashing volumes of cold water upon a pupil. 

Breathing Chlorine Gas. — With all precautions, chlorine 
gas is occasionally inhaled, causing violent and prolonged 
fits of coughing. Relief is obtained by cautiously inhaling 
ammonia. 

Burns from Acids. — Strong acids, especially when hot, 
make very painful wounds in the flesh. The hot vapors 
of some acids like hydrobromic and bromic acids will act 
upon the skin producing sores. Wash such wounds im- 
mediately in a dilute solution of ammonia, caustic soda 



GENERAL MANIPULATIONS. 43 

or potash, and bind up the injured parts in cloths wet in 
a solution of sodium carbonate. 

Burns front Phosphorus. — The wounds are deep, pain- 
ful, and hard to heal. Bathe the wound in carbonate of 
soda solution, then bind about it cotton-batting or lint 
soaked in the same solution, till the pain subsides. Then 
bandage the wound, binding upon it bits of lint soaked 
in glycerine diluted with one volume of water. Spirits of 
turpentine are sometimes used. 

Burns and Scalds. — Reduce the pain and heat imme- 
diately by the free use of ice. If this is not procurable, 
bind on the pulp of a raw potato, finely scraped, and renew 
it frequently. If the skin is not abraded, great relief is 
obtained by covering the injured surface deeply with soft- 
soap. After the pain has somewhat subsided, wrap up the 
wound carefully, and soak the bandage with olive-oil, or, 
better, the well-known family remedy, "Pond's Extract of 
Witch Hazel." 

Action of Alkalies on the Skin. — The smarting sensation 
caused by the caustic action of aqua ammonia and like sub- 
stances is relieved by washing the skin with carbonate of 
soda solution. 

Acid Stains on Clothing may be made less conspicuous, 
and sometimes obliterated by occasional applications of 
aqua ammonia or a solution of caustic soda or potash. 

Nitric Acid Stains upon the Skin may be reduced some- 
what, but not wholly effaced, by rubbing spirits of tur- 
pentine upon them. In a few days the stained cuticle 
may be scraped off. 



CHAPTEE V. 

EXPERIMENTATION WITH HYDROGEN, OXYGEN, WATER, 
AND AIR. 

60. Hydrogen. — No materials are more satisfactory and 
reliable for generating H than granulated zinc and H CI. 
The joints of the generator must be very tight, and the 
acid added in small successive quantities, not more than a 
teaspoonful at a time. A drop or two of a solution of 
platinum perchloride will sometimes make the evolution 
of the gas much more prompt and copious. The purity of 
the H must always be established before a flame is applied 
to it. Fill test-tubes, by displacement of water or air, with 
the gas and apply a burning match. As long as it burns 
with a shrill noise it is unsafe to use a quantity. The 
gas is safe when the flame passes quietly and steadily up 
through the tube. 

61. Diffusibility of Hydrogen. — In showing the diffu- 
sion through a septum of plaster of paris in a glass tube 
make the plug from a sixteenth to an eighth of an inch 
thick, allow it to become perfectly dry before using, and 
avoid wetting it in the least during the experiment. After 
filling the tube with H, place the open end in a vessel of 
colored water. 

The same fact is shown more simply. Place a sheet of 
clean blotting-paper over a jet of H, and apply a match 
above the paper. 

62. Hydrogen Tone. — Glass tubes from one-half to one 
inch in diameter, and from two to three feet in length, are 



EXPERIMENTATION. 45 

right for this experiment. Either fasten the tube firmly 
into the burette-holder in a vertical position and pass the 
jet tube (which js inserted into the rubber delivery tube 
of the generator) upward into the tube, or attach a long 
glass delivery tube, terminating in a jet, in a vertical 
position to the generator and pass the tube squarely down 
over the flame. 

63. Oxygen. — The general directions given in Chap. IV. 
Sects. 47-50, in regard to heating flasks and collecting gases 
over water together with the full directions usually found 
in chemical text-books, will furnish sufficient aid for the 
preparation of small quantities of oxygen. While the ex- 
treme diffusiveness of hydrogen renders it unsafe to pre- 
pare it more than one or two hours in advance of using 
it, oxygen can be kept an indefinitely long time in good 
gas-holders or bladders. Oxygen should not, however, be 
kept long at a time in rubber bags, as it hardens and 
destroys the quality of the rubber very rapidly. It is more 
convenient, and much cheaper, to prepare this gas in large 
quantities, ready for use at a moment's notice. A large 
glass flask may be used, but it is a gain to purchase an 
iron retort, made for the purpose, with an accurately fitted 
iron stopper and iron delivery tube, cost $ 3.00. Select 
a retort with a well-fitted stopper without a clamp. 

64. In Heating Large Quantities of the Mixture, the 
proportions of equal weights of K CI 3 and Mn 2 are by 
far too wasteful. Use, instead, four parts of the chlorate 
with one of the black oxide of manganese. A little more 
gas may be obtained by pulverizing the chlorate crystals, 
but it is safer and altogether better not to do so. Be 
sure that the two substances are thoroughly mixed. Each 
pound of the mixture, prepared as directed, furnishes about 
thirty gallons of gas. 

65. Both Oxygen and Hydrogen should be Purified by 



46 ELEMENTARY CHEMICAL TECHNICS. 

passing them through a wash-bottle (see Sect. 43), contain- 
ing for H pure water, for either pure water or a dilute 
solution of caustic potash or soda. 

66. The following Precautions, carefully observed, will 
avert all danger in preparing the gas : 

First. The mixture must be absolutely free from or- 
ganic matter or an explosion will result from the heating. 
Commercial oxide of manganese is often adulterated with 
charcoal or bone-black. Ascertain the purity of the mate- 
rials by heating a very little of the mixture in a test-tube. 
If the gas passes off quietly, leaving a grayish residue, it 
is safe for use. (Keep the mixture in a wide-mouthed, 
well-stoppered bottle away from dust and impurities.) 

Second. Heat the retort gently at first and lessen the 
intensity somewhat when the gas begins to come off abun- 
dantly. 

Third. Do not let any rubber tubing that may be used 
become highly heated lest a compound of hydrogen, explo- 
sive with oxygen, be generated. 

Fourth. Set the rubber bag or other receiver consider- 
ably higher than the level of the wash-bottle in order that 
no accidental rush of the gas may force water and solid 
particles over into the bag. 

Fifth. Do not let the retort cool down at any time while 
connected with the wash-bottle, sufficiently to cause a re- 
sorption of water. 

When the gas is all driven over, or the bag is full, slip 
off the tube connecting the wash-bottle and the bag from 
the former, and instantly close the stop-cock of the bag. 
Then disconnect the wash-bottle from the retort and re- 
move the heat. When the retort is cool enough, rinse it 
out thoroughly with hot water, and dry it scrupulously. 

67. The uses for oxygen in the laboratory are many, 
and the list of experiments to be performed with it is 
very long. 



EXPERIMENTATION. 47 

But text-books suggest so many that a considerable number 
in this work would be superfluous. 

68. Combustibility of Oxygen. — It may be made to burn 
in an atmosphere of H 3 N or H or illuminating-gas. In 
illustrating the first, select a somewhat wide-mouthed flask. 
Draw a piece of glass tubing to a jet-point and bend this 
end back in the shape of a fish-hook, so that it will readily 
pass down into the neck of the flask, and connect it with 
the delivery tube of the oxygen bag. 

Place a little strong ammonia in the flask, and heat it. 
When the fumes begin to come from the neck abundantly, 
turn on the 0, lower the bent tube into the neck, and apply 
a flame to the jet. 

Fit a cork to the top of an argand lamp-chimney. 
Through the cork pass a delivery tube connected with a 
supply of H or illuminating-gas. Insert a long, straight 
piece of glass tubing drawn to a fine jet into the oxygen 
delivery tube. Fasten the chimney in a vertical position, 
turn on the H or illuminating-gas, ignite it at the bottom, 
and pass the jet-tube of up into the chimney. 

69. In Preparing Mixed Gases, place the one-third part 
of in the tubulated jar first, and then run in the H. 
Avoid every possibility for fire to reach the mixed gases. 
If masses of bubbles are exploded on the surface of suds, 
never use a mass larger than can be covered with the two 
hands. The tremendous percussion does temporary and 
sometimes permanent injury to the "membranum tympani" 
of the ear. Soap-bubbles will be much more durable if to 
a suds made by dissolving as much hard-soap as possible 
in warm soft water a little glycerine is added. 

70. The Principle and Working of the Compound Blow- 
pipe can be profitably illustrated even with bladders of 
two gallons capacity. If the school possesses good rubber 
bags of a capacity of forty gallons or more, it will pay to 



48 ELEMENTARY CHEMICAL TECHNICS. 

purchase a blowpipe, either with or without a mounting- 
stand, at a cost of from $ 3.50 to $ 10.00. 

Fig. 17 represents a home-made substitute which is safe, 
and will yield very satisfactory results, a b is a piece of 
sheet-cork 2^ x 4 x 2 inches in dimensions. 
a eg c h c d is a common mouth blowpipe, e f is a 

|\ gpQ 1P\^ piece of straight brass or tin tube about the 
V size of No. 3 glass tubing. If nothing better 

y." u rf presents, use the larger part of another mouth 

//$.//. blowpipe. The lime-holder g was in one in- 

stance made of a brass thimble with a long 
screw passed through the top. The thread of the screw 
turning in the cork served as a means for revolving and 
adjusting the height of the lime. A piece of fine wire- 
gauze should be folded over the end of the tube at e and 
securely wired to the tube. The end of the tube at d must 
be covered in the same wa} r , and the gauze wired on very 
securely and neatly, so that the rubber tube will slip on 
over it. 

Clamp the end b of the block of cork firmly into the 
pipette or iron retort-holder. Connect / by means of 
rubber tubing with the hydrogen gas-bag. (If available, 
illuminating-gas will do almost as well, connecting directly 
upon the tube of the common burner.) Then connect d 
with the oxygen holder. First turn on the H and light 
it at e. Then slowly and cautiously turn on the 0. Regu- 
late until a slender blue flame is seen streaming straight 
out from the end of the oxygen tube. In this flame steel 
watch-springs will burn brilliantly. Small pieces of soft 
glass tubing and fine platinum wire will melt and drop. 

71. Lime Cylinders securely packed in an air-tight tin 
box can be purchased for $ 1.50 per dozen. For purposes 
of illustration they can be prepared equally well. Select 
a lump of quicklime as hard and firm as possible. From 



EXPERIMENTATION. 49 

it, with an old saw, cut out blocks an inch square and three 
inches long. Then whittle out these blocks round and 
smooth of the proper size to fit g. (Several of these cyl- 
inders can be made at once, and kept for a long time, if 
packed in dry sand in a fruit-jar, with the cover securely 
screwed on.) Let the point of the blue flame play directly 
upon the lime, and if it is to be used for some time, turn 
the lime occasionally so as to direct the flame upon a fresh 
spot. To obtain the best lime-light requires a little prac- 
tice. Too much oxygen cools the lime, too little reduces 
the temperature of the flame. Too much hydrogen, es- 
pecially if illuminating-gas is used, tends to crumble the 
lime. Remember that the pressure upon either of the gas- 
holders must not be varied an ounce without shutting off 
both and thus extinguishing the flame. 

72. A Full Illustration of the Chemical and Physical 
Properties of Water and Air is important. 

73. Physical Properties of Water. Expansion when 
Heated. — Fit a cork to a small test-tube and pass through 
the cork a piece of No. 3 or 4 glass tubing seven inches 
long. Make the joints very tight ; fill the test-tube and 
the small tube up two or three inches completely (allow- 
ing no air-bubbles to become entangled) with cold water. 
Mark the limit of the water in the small tube by tying 
a thread tightly about the tube and heat it gently. 

Expansion below 89.2° F. — Illustrate this by bursting 
a thin glass bottle. Be sure that the bottle is completely 
filled up to the cork, and the latter securely tied into the 
neck. Use a mixture of two parts of powdered ice and one 
of salt in a wooden vessel. 

Solution of Mineral Salts in Well-water. — Demonstrate 
this by distilling well-water. Expensive apparatus is not 
needed. A glass retort and receiver even are not essential. 
Fit up a flask with cork and long glass delivery tube, so 






50 ELEMENTAKY CHEMICAL TECHNICS. 

bent as to pass into the neck of a small flask which is to 
be placed in a nappie of cold water and covered with a 
wet towel. Evaporate very gently on a perfectly clean 
piece of tin or cover-glass a few drops of water from each 
flask. The nndistilled water will leave a film of mineral 
salt. 

The Nature of the Residue can be approximately ascer- 
tained by processes within the scope of this work. 

Evaporate the water in the flask until but a few spoon- 
fuls remain. Place portions of this residue in four test- 
tubes, (a) Add to the first half a dozen drops of HN0 3 
diluted with two volumes of water, and two drops of a 
solution of barium chloride. Shake and hold up to the 
light. A dim milkiness is proof of a sulphate present. 

(b) To the second add the same quantity of HN0 3 
and two drops of silver nitrate. The slight cloudiness 
that may result will show a chloride. 

(c) To the third add four or five drops of ammonia 
water and one or two of a solution of ammonium oxalate. 
If a white cloudiness appears it is evidence of a calcium 
salt. 

(d) To the fourth add a few drops of H CI and run in 
H 2 S gas. If a very slight brownish tinge is imparted to 
the water a lead salt is present. 

Solution of Gases. — Fill a flask and its glass and rubber 
delivery tube completely with water. Heat the flask, and 
the dissolved gases will be expelled, and can be collected 
over water in sufficient quantity to test. 

Solution of Organic Matter. — Make a pale pink solution 
of potassium permanganate, and add one or two drops of 
sulphuric acid. Soak bits of paper in hot water for some 
time and pour the liquid into the permanganate solution. 
If the paper has been dissolved by the water in the 
slightest degree, the permanganate, upon standing over 



EXPERIMENTATION. 



51 




Fig J 8. 



night, will give up and lose its color. Exclude the 
ox}" gen of the air. 

74. Chemical Properties of Water. 

For Electrolysis of Water, see Chapter XII. 

The Weight Ratios of hydrogen and oxygen in water can 
be demonstrated with some degree of accuracy, even before 
a class, by the following experiment : 

a is an ordinary hydrogen generator ; b, a small wash- 
bottle, one-third full of strong H 2 S 4 , to absorb the 
moisture from the H j c is a tube of hard glass, one inch in 
diameter and twelve in length, containing a small quantity 
of copper oxide. Both ends of the tube are closed with 
close-fitting corks, through which are passed pieces of glass 
tubing, No. 4, three inches in length ; d is a U-tube filled 
with lumps of caustic soda, or, better, calcium chloride. 
Note the exact weights of the copper oxide and calcium 
chloride before placing them in the tubes. It is well to 
weigh the calcium chloride in the U-tube, as it is somewhat 
difficult to remove that entirely for weighing after it has 
become partially dissolved in the moisture. After the 



52 ELEMENTARY CHEMICAL TECHNICS. 

apparatus is all in readiness, pour the acid into the H 
generator. Attach a piece of rubber tubing to e, and with 
it fill an inverted test-tube by displacement of air (passing 
the rubber tubing clear up to the bottom of the test-tube). 
Burn the gas thus gathered, and continue to test till the 
hydrogen burns quietly. Then remove the rubber from e, 
and with Bunsen burner or alcohol lamp heat the Cu very 
cautiously at first, constantly moving the lamp to and fro. 
Keep the mass just below a red glow. The sides of the 
tube will quickly become covered with moisture from the 
water formed, which, as the tube becomes hotter, will all 
pass on into the U-tube. When the oxide is all converted 
into bright copper, arrest the heating, and as soon as 
practicable weigh the copper remaining and the calcium 
chloride. A deduction similar to the following may be 
obtained : 

GRAIXS. 

Weight of Cu before heating 100 

" " after " 80 

" in water formed 20 

" Ca Clo in U-tube 480 

" " after absorbing water . . . 502.5 

" water formed 22.5 

{Weight of water) {Weight of O) (Weight of H) 

22.5 grains. — 20 grains = 2.5 grains. 

( Weight of O) ( Weight of H) 

20 : 2.5 = 8 : 1. 

75. Preparation of Hydrogen Dioxide. — Barium dioxide 
is needed for the purpose. It may be purchased of most 
dealers in chemicals, or prepared with a little trouble, as 
directed under the subject of Barium. See Sect. 184. 

Mix in an evaporating-pan a little pulverized dioxide 
with a little water to a consistency of thin cream. Then 
add strong H CI in a sufficient quantity to make a quick 
solution. The liquid will be impure hydrogen dioxide, but 



EXPERIMENTATION. 53 

-will show all the properties of the substance quite well. 
Beautiful experiments, similar to those usually given under 
ozone, illustrative of its bleaching and oxidizing power, may 
be performed with this liquid. 

76. For Synthesis and Analysis of Water, see Sects. 253 
and 256. 



AIR. 



77. Physical Properties. Atmospheric Pressure. — Fit a 
cork closely to a thin glass flask. Fill the flask half full 
of water and heat it. After the water has been boiling 
vigorously some minutes, remove the flask from the lamp 
and instantly press the cork in firmly. When the flask is 
thoroughly cooled it will be shivered by external pressure. 

Vapor of Water in Air. — Fill the bend of a U-tube 
with bits of caustic potash, draw a steady draught of air 
through the mass by connecting the tube with an aspirator- 
bottle, or the tube described in Sect. 30, Fig. 7. The 
potash will become wet, and finally dissolve in the water 
seized from the passing air. Or fill a tin fruit-can with 
a freezing mixture and note the condensation upon the 
outside. 

Carbon Dioxide in Air. — Fill the bend of a U-tube 
with lime-water or baryta-water and pass a draught of air 
through it for a long time. Or, more simply, leave a little 
lime-water in a shallow vessel, like a saucer, exposed to the 
atmosphere for twenty-four hours. 

78. Composition is usually demonstrated by shutting a 
measured quantity of air into a straight eudiometer tube, 
inserting a piece of phosphorus, and noting the decrease of 
volume by the oxidation of the P. Text-books direct to 
perform the experiment over mercury, but water may be 
used, if rigid accuracy is not sought after, and the experi- 



54 ELEMENTARY CHEMICAL TECHNICS. 

ment be finished in 10 or 12 hours. A convenient way to 
insert the P is to make a loop at the end of a piece of 
wire of proper length, melt the P under hot water, thrust 
the loop into the molten mass, and allow it to remain 
till the water is cooled. The wire can then be removed 
with the phosphorus adhering in the form of a pellet, and 
the end passed up into the confined air in the tube. 



CHAPTEE VI. 

EXPERIMENTATION WITH NITROGEN COMPOUNDS. 

79. Preparation of Nitric Acid. — Use Chili saltpetre in 
preference to nitre, 4 parts by weight of the salt to 5 of 
H 2 S0 4 . Heat the vessel moderately, to prevent frothing. 

80. Nitric Acid may be easily Decomposed with Evolu- 
tion of Oxygen. — Fill a bowl of a "TD" pipe half full 
of HN0 3 . Place the pipe in the retort-stand at such an 
angle that the acid will penetrate § of the way through the 
stem. Heat the stem intensely in a Bunsen flame and pass 
the gas into a little bottle over water by means of a little 
rubber tubing slipped over the end of the stem. 

81. Nitrous Oxide. — The preparation of N 2 by the 
decomposition of ammonium nitrate is made much more 
interesting by interposing between the heating flask and 
the receiving jar a small bottle fitted up like the wash- 
bottle (Chap. V. Fig. 18 b). Let the inside of the bottle 
be perfectly dry and set in a basin of cold water. The 
water generated in the decomposition will condense and 
be retained in the bottle. Make the different pieces of 
the delivery tube of glass with the shortest rubber connec- 
tion possible, as rubber is acted upon by the laughing-gas. 
The same experiments in combustion can be performed 
with N 2 as with pure O with nearly equal brilliancy. 
Soap-bubbles filled with a mixture of equal parts of N 2 
and H explode with deafening report. 

82. Nitric Oxide. — In obtaining NO by the action of 

55 



56 ELEMENTARY CHEMICAL TECHNICS. 

HN0 3 , on copper clippings, use an hydrogen generator. 
Cover the clippings and mouth of the thistle-tube with 
water. Add the acid in small successive quantities, not 
more than a teaspoonful at a time, and wait each time until 
the added portion is working before pouring in more. Con- 
tinue this cautious addition till the evolution is sufficiently- 
rapid. Phosphorus and magnesium ribbon will burn in 
NO, if they are allowed to get well burning before they 
are thrust into the gas. 

83. Nitric Oxide will give up its Oxygen. — (a) Fill a 
quart jar with N 0. Set the jar mouth upward on the table, 
covering it with a glass plate. Pour in a half teaspoonful 
of C S 2 . Note the light flash as the N gives up its 
oxygen to the carbon, and the sulphur of the bisulphide 
may be detected on the sides of the jar. 

(b) Dissolve as large a crystal as possible of ferrous 
sulphate in a test-tube full of water. Add 3 or 4 drops 
of H 2 S0 4 . Shake well and insert in water over the 
mouth of the delivery tube from a bottle generating N 0. 
Fill the test-tube half full of the gas. Close the mouth 
of the tube with the finger, remove it from the water and 
shake thoroughly. 

84. Nitrogen Trioxide is made by exposing N to of 
the air. 

85. Nitrogen Tetroxide. — Place a little starch in a flask. 
Pour on it a small quantity of HN0 3 and warm the flask. 

86. To form Nitrous Acid run the gas into water. Test 
it with litmus-paper. 

87. The production of Nitrogen Pentoxide by the action 
of CI upon nitrate of mercury is too difficult to be included 
within the scope of this work. 

88. Ammonia. — Bottles of aqua ammonia should always 
be kept in a cool place and never exposed to warm sun- 
light. Never heat necks of bottles containing it to remove 



BKIKF INSTITUTES OF GENERAL HIS- 
TORY. By E. Benjamin Andrews, d.d., 
ll.d., Professor of History iu Brown Uuiversity. 
±52 pages. Cloth. Price, $2.00. Silver, Rogers & 
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This volume is precisely what its uame implies — 
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twenty paragraphs, after the fashion of the best Ger- 
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pact, orderly, and rounded whole. Especially to 
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All unimportant details are ignored, the most impor- 
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The result is a precipitate rather than an outline or 
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This is confidently believed to be for classroom use or 
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EXPERIMENTATION WITH NITROGEN COMPOUNDS. 57 

refractory glass stoppers, and always remove the stoppers 
of nearly filled bottles with the utmost caution. The gas 
is made by heating together 2 parts of ammonium chloride 
with one part of quicklime. 

For ordinary experimental purposes obtain the gas by 
heating aqua ammonia in a flask provided with a delivery 
tube. 

89. Combustibility of Ammonia in Oxygen. — Fig. 19 rep- 
resents a piece of apparatus for the purpose. Fit to the top 
of an argand lamp-chimney a cork. Pass through 
the cork a piece of No. 4 tubing, drawn to a jet, yj 
and reaching within half an inch of the base of 
the chimney, and a short delivery tube b. Connect 
c with the flask of aqua ammonia, and b with a 
gas-bag of 0. Fasten the chimney in an inverted 
position in a pipette-holder. When the heat be- 
gins to expel the H 3 1ST abundantly through the fine c 
jet, turn on the 0, and when the chimney is full /<J 

of the latter gas apply a match to the jet. A simple but 
satisfactory method is to insert a glass jet-tube, bent into 
the shape of a fish-hook, into the rubber delivery tube of 
a flask in which aqua ammonia is being heated, then lower 
the jet-tube into a jar of oxygen gas and apply a flame 
to the ammonia gas as it escapes. 

90. For Electrolysis of Ammonia, see Sec. 255. 

91. Solubility of Ammonia in Water. — Fit a cork to a 
wide-mouthed horse-radish bottle. Through the cork, and 
reaching two-thirds of the way to the bottom of the bottle, 
pass a piece of No. 4 tubing not drawn to a jet-point. Pro- 
vide a basin of cold water colored with purple cabbage 
solution or litmus solution reddened with the least possible 
amount of acid. Connect the glass tube of the bottle with 
the rubber delivery tube of a flask containing strong aqua 
ammonia and fastened in the retort-stand ready for heating. 



58 ELEMENTARY CHEMICAL TECHNICS. 

Holding the bottle in an inverted position and the cork 
very loosely in the neck to allow the escape of the con- 
fined air, fill the bottle with ammonia gas. Let the liquid 
in the flask boil vigorously. The moment when the bottle 
is full of gas can be judged pretty accurately by holding 
a piece of tumeric paper (yellow litmus) or a glass rod 
wet in H CI at the mouth of the bottle. When all is ready, 
push the lamp from under the flask, slip the rubber tube 
off the glass tube of the bottle, and instantly placing the 
finger firmly over the end of the glass tube, press the cork 
very firmly into the bottle and lower the tube into the 
colored water and remove the thumb. In a short time the 
liquid will be seen creeping up the tube ; as soon as the first 
drop enters the bottle a partial vacuum will be made, and 
the bottle will fill with water with a violent rush. If the 
absorption is not sufficiently prompt, tip the bottle down on 
one side so that a few drops of the liquid will run up the 
tube into the bottle. A cabbage solution will be turned 
green, red litmus blue. If failure follows two or three 
trials, rinse the bottle with cold water, wipe it out, and 
try again. Ammonia gas should always be collected by 
downward displacement of air. 

92. Oxidation of Ammonia, under the subject of Plati- 
num, see Sect. 237. 

93. Ammonia may be Decomposed in a manner identical 
with that employed in the decomposition of C 2 , using 
metallic potassium. See Sect. 127, method a. 



CHAPTER VII. 

FLUORINE, CHLORINE, BROMINE, AND IODINE, AND THEIR 
COMPOUNDS. 

94. Hydrofluoric Acid. — The only compound of fluorine 
to be made in the laboratory is hydrofluoric acid. Its 
preparation and action on glass are described in Chap. II. 
Sect. 27. 

95. Chlorine. — The preparation of CI from H CI with 
Mn 2 is often unsatisfactory because the CI gas is soon ex- 
hausted and only steam is driven over into the collecting jar. 
This may be in part obviated by adding successive portions 
of H CI. One of the best methods of obtaining an abun- 
dant supply of the gas of good quality is the following: 
Mix four parts by weight of " coarse fine " salt with three 
of Mn 2 ; place them in a flask and add water enough to 
form a thin paste ; rinse the mixture around in the flask 
well and add two parts of H 2 S0 4 . Insert the stopper 
and delivery tube and heat very moderately. 

96. To burn Phosphorus in CI, place a piece the size of 
a pea, well dried, in a deflagrating spoon and lower into a 
large jar of gas. It may be some time before the ignition 
takes place. 

97. Combustion of Antimony. — It is not necessary to 
dry the CI to burn Sb in it, if the jarful is collected when 
the gas is being evolved abundantly, anci if the Sb is finely 
pulverized. It is well to sprinkle fine sand over the bot- 
tom of the jar before collecting the gas, as the particles of 
antimony burn into the glass. 

59 



■5. 

60 ELEMENTAEY CHEMICAL TECHNICS. 

98. Chlorine Water. — A stronger solution of CI in 
water can be obtained when the water is quite cold, and 
if the gas is subjected to a little tension. This can be 
brought about thus : place a cork, water-tight, in the mouth 
of a glass retort in the place of the glass stopper. Com- 
pletely fill the bowl, but not the long neck of the retort, 
with cold water. Place the retort wrong side up in a nap- 
pie and pass a piece of glass tubing down the length of the 
neck and well into the bowl. Connect this tubing with the 
rubber delivery tube from the CI generator and run in the 
gas. The water will gradually be forced up the neck of 
the retort, and overflow into the nappie. The water will 
exert pressure enough to cause a greater quantity of gas 
to dissolve. 

99. To show Decolorizing and Bleaching Power of CI. — 
Use a decoction of logwood or cochineal. Soluble indigo 
is more difficult of reduction. For bleaching use pieces 
of bright calico, wet. 

AVrite with common ink upon a piece of printed paper 
and place it in a moist condition in a jar of CI. 

100. Direct Union of Chlorine and Hydrogen. — (a) Draw 
a piece of glass tubing, No. 3 or 4 one foot in length, to a 
fine jet. Bend this end up in the shape of a fish-hook, so 
that the shorter arm shall be about two inches in length. 
Attach this to the rubber delivery tube of an hydrogen 
generator, and after properly testing, light the jet of H 
and lower it into a jar of CI. Test for the formation of 
H CI at the mouth of the jar, using blue litmus-paper. 

(b) Fill a large bulging jar — an olive pickle-jar is 
excellent — with CI, and pass down into it a fine jet of 
burning H, using a straight tube in place of the bent one. 
A peculiar deep bass hydrogen tone will be produced. 

(c) The Combustion of Turpentine in CI is more trouble- 
some to show than is generally indicated in text-books. 



COMrOUNDS. 61 

But its accomplishment is assured if the following pre- 
cautions are observed: The turpentine must be of good 
quality and fresh, not oxidized in the least. Buy a little 
of a druggist for the sake of a better quality. Heat 
the turpentine very hot over the water-bath (see Sect. 
40). Soak pieces of blotting-paper in the turpentine and 
transfer them to the jar of gas as promptly as possible. 

(d) Fill the small stoppered bell-jar (Sect. 38) with CI 
water. Test the water with litmus-paper. Then set in as 
strong a light as possible for several hours. Test again 
with litmus-paper for acid. Press the jar deep into water, 
open the stop-cock and test the gas, which should be oxy- 
gen. 

(e) Select a piece of glass tubing about a half -inch in 
diameter and twenty inches long. Fit a cork to one end 
and fill it within two inches with strong chlorine water. 
Fill the remaining two inches with ammonia water. Place 
the finger over the end and invert it in a wine-glass of 
chlorine water. Note the bubbles, and after a time place 
the finger under the mouth to prevent the liquid from 
falling in the tube, remove the cork, and test the free 
nitrogen in the top. 

(/) Fill a soda-water bottle with hot water and invert 
it over a pan of the same. Run in hydrogen till the bottle 
is half filled. Then wrap a towel around it and run in CI 
till the bottle is filled, leaving a few drops of water in it. 
Shake the bottle thoroughly, and, holding it horizontally 
with the mouth averted, bring a lighted candle to the 
mouth. After the explosion test the fumes in the bottle 
with blue litmus-paper. 

(g) A brilliant modification of this may be made upon 
a sunny day. Select a pint bottle of clear white and rather 
thin glass. Ascertain and mark upon the outside with a 
file the point where it is just half full. Fill it as described 



62 ELEMENTARY CHEMICAL TECHNICS. 

in the preceding, but be careful to have the volumes of the 
two gases exactly equal. Arrange the towel so that the 
bottle can be slipped instantly, and with no danger of 
entanglement, from its folds, press in a cork firmly, carry 
it out into the sunlight and fling the bottle high in air. 
It will be shivered with a loud report. 

101. Preparation of "Butch Liquid." — Fill a small bell- 
jar with hot water and invert over a pan of the same. 
Eun in chlorine till it is half filled. Fill the remaining 
space with ethylene (see Sect. 123 b) and leave in strong 
light a few minutes. The oil will gather on the sides of 
the jar and the surface of the water. 



HYDROCHLORIC ACID. 

102. Preparation of Hydrochloric Acid Gas. — Text-books 
direct to fuse the salt used, that a smaller surface may be 
exposed to the action of the H 2 S 4 . This is not necessary 
if well-dried "coarse fine" salt and H 2 S0 4 diluted, one 
volume in four, are used. Mix them in the proportions by 
weight of two parts of the latter to one of the former, and 
heat in a flask with delivery tube. Collect gas by upward 
displacement of air. 

103. Solubility in Water. — Eepeat the experiment in 
Sect. 91, with these modifications : fill the fountain-bottle 
with H CI gas, holding the mouth up. Invert the bottle 
over water colored with blue litmus. 

104. Relation to Combustion. — Burn magnesium ribbon 
in a jar of the gas. 

105. Preparation from Aqueous Solution. — The gas some- 
what contaminated with vapor of water can be obtained by 
simply heating the commercial acid. The gas may be dried 



COMPOUNDS. 63 

by causing it to bubble through strong H 2 S 4 in a wash- 
bottle ; or, better, fill the wash-bottle with bits of pumice- 
stone soaked in the acid, and pass the gas through. 

106. Decomposition. — (a) By Electrolysis, see Sect. 258. 
(l>) By Sodium. In the same way as C0 2 , see Sect. 137 a. 
Use dry gas, and in place of c d a jet-tube turned upward. 
Ignite the H at d. 

107. Chlorine Tetroxide. — Put a few crystals of K CI 3 
in a wine-glass ; cover with water, and add a few drops of 
H 2 S 4 through a thistle-tube. 

Modify this by mixing a few tiny pieces of P with the 
KC10 3 . They will burn under water. 

108. Formation of Potassium Chlorate. — Fit a cork and 
small glass delivery tube bent at right angles to a piece 
of glass tubing a half-inch in diameter and four inches 
long. Place the mouth of this tube in a concentrated 
solution of caustic potash (make the solution as strong 
as possible, using warm water). Pass CI gas into the tube, 
first sending it through a wash-bottle containing a little 
hot water. 

109. Bromine. — This element is put up in ounce-bottles, 
for sale by all dealers. But it is pretty sure to leak after 
it is once opened, and corrode everything in its neighbor- 
hood. Enough can be easily prepared from potassium 
bromide to show the element and most of its properties. 

Weigh out and mix four parts of finely pulverized K Br 
and three of Mn 2 • Place in a test-tube, add four parts 
of H 2 S 4 and heat gently. The heavy vapors can be 
poured out into other test-tubes for use. Or a cork and 
delivery tube may be used in the tube. The tube must 
be of glass, quite short, and bent downward at right angles 
close to the cork, for the heavy vapor is hard to expel 
from the tube. If liquid Br is at hand, place a few drops 
in a small jar with a dropping-tube. Cover the jar loosely j 



64 ELEMENTARY CHEMICAL TECHNICS. 

warm it a very little, and in a few minutes it is ready for 
use. Avoid inhaling the vapor. 

110. Experiments. — (a) Bleach blue litmus-paper, (b) 
Pour some of the vapor into a test-tube containing a little 
water and shake to form bromine water, a powerful bleach- 
ing agent, (c) Drop finely powdered Sb into the vapor. 
(d) Burn phosphorus in it in the same manner as in 
chlorine, using a pint-jar. (e) Fill a small test-tube with 
bromine water and a few drops of C S 2 and shake. After 
it settles, note the clearness of water and the deep orange 
color of the globule at the bottom. 

111. Starch Compound. — To a solution of starch add a 
solution of KBr, and pour in a little HN0 3 and shake. 
Make both solutions strong. Or add a very little bromine 
vapor to a solution of starch. 

112. Hydrobromic Acid. Preparation. — Place equal 
weights of KBr and H 2 S0 4 in a test-tube and heat. 

113. Iodine. Preparation. — The Kesublimed Iodine of 
the druggist is cheap and most excellent for all experi- 
mental purposes, but it can readily be prepared from an 
iodide. Place in a test-tube equal weights of K I, Mn 2 and 
H 2 S 4 and heat. Hold the tube obliquely and invert over 
its mouth another cold tube. 

114. Affinity for Phosphorus. — Place crystals of iodine 
and thin flakes of phosphorus in contact with each other 
on a piece of brick. 

115. Starch Compound. — ( a ) To a dilute solution of 
starch add iodine dissolved in alcohol, or a solution of K I. 
(b) Drop some of the solution very dilute upon a fresh 
slice of raw potato. (In testing iodine with starch solu- 
tion it must be remembered that the solution needs to be 
fresh and cold.) (c) To a dilute solution of starch add a 
solution of K I and shake well. Then pour in a few drops 
of H N 3 and shake again. 



COMPOUNDS. 65 

116. Mercury Iodide. — Fasten a piece of large glass 
tubing, five or six inches long, in a burette-holder in a 
horizontal position. Insert a globule of Hg and a few 
crystals of I. Place a moderate* heat under the Hg till it 
vaporizes. The ends of the tube may be loosely closed 
with corks. Perforin this experiment under the hood. 

117. Hydriodic Acid may be prepared contaminated with 
iodine vapor by heating equal weights of K I and H 2 S 4 
in a test-tube. 



CHAPTER VIII. 

EXPERIMENTATION WITH CARBON AND ITS COMPOUNDS. 

118. Impure Carbon by the Distillation of Wood. — If a 

test-tube is fitted with cork and delivery tube, filled one- 
third full of excelsior or fine shavings and heated, a com- 
bustible gas may be gathered over water and impure carbon 
will remain in the tube. This " destructive distillation " 
will also yield a tar and a vapor in the tube which gives 
an acid test. 

119. Porosity of Charcoal. — (a) Fasten a piece of char- 
coal, one-half inch in diameter, to a piece of annealed wire, 
one foot long. Heat the coal to redness, and covering it 
deeply with fine sand, let it cool. Fill a test-tube with 
ammonia gas by downward displacement of air. Bend the 
wire so that the charcoal can be passed up nearly the whole 
length of the tube. Insert the charcoal and invert the tube 
over a wine-glass full of mercury. 

(b) Fill a test-tube, by downward displacement of air, 
with H 2 S. Place the hand over the tube and turn it right 
side up. Drop in half a teaspoonful of powdered charcoal 
and shake thoroughly. Note the disappearance of the 
odor. 

120. Decolorization by the Action of Charcoal. — Use a 
solution of laundress's blueing (dilute) or of litmus, soluble 
indigo, or purple cabbage decoction. Cochineal solution is 
still better. Macerate 2 or 3 cochineal grains in a mortar 
with a little water. Add this pulpy mass to 2 ounces of 



CARBON AND ITS COMPOUNDS. 67 

water and stir well. Add a teaspoonful of boneblack and 
stir very thoroughly. Then filter, more than once if neces- 
sary, to make the liquid perfectly clear. 

121. Reducing Power of Carbon is illustrated by the 
usual experiment of directing the mouth blowpipe flame 
upon litharge on a piece of charcoal. Dry lead carbonate 
may be used instead of litharge. 

Or heat one part powdered charcoal and ten of copper 
oxide in a test-tube, fitted with cork and delivery tube. 
Run the resulting gas into lime-water. 

122. Formation of Lampblack. — Place upon a piece of 
sheet-iron or tin, supported upon a block of wood, a bit 
of tar or blotting-paper soaked in spirits of turpentine, or 
fill an alcohol lamp with turpentine ; set on fire and invert 
a bell-jar over it, propping up the jar about a half -inch on 
one side. 

123. Hydrocarbons, (a) Methane. — Made as described 
in all text-books by heating together sodium acetate, caustic 
soda, and quicklime in the proportions by weight of 1, 2, 
and 4 parts. Or soak small pieces of lime in vinegar and 
heat them. Do not collect the gas for some time, that the 
excess of steam may pass off. 

(b) Ethylene. — Mix carefully one part by weight of 
alcohol with four of strong H 2 S0 4 , pouring the acid into 
the alcohol, stirring all the time. Heat the flask gently, 
and collect the gas over water in the stoppered receiver 
described in Sect. 38. To burn this heavy gas, open the 
stop-cock, and press the jar deep into the water in the 
pneumatic tank. If the gas has been collected in an ordi- 
nary wide-mouthed jar pour in water, as the gas burns, to 
drive it upward to the mouth. 

(c) Acetylene can be very easily prepared by imper- 
fectly burning illuminating-gas. Unscrew a Bunsen burner 
tube, turn on the gas, light it, and replace the tube. Then 



68 



ELEMENTARY CHEMICAL TECHNICS. 




place the burner under an inverted tin tunnel. Connect 
the tunnel by rubber tubing with an aspirator-bottle, and 
draw the product, which will be impure acetylene, into 
the bottle. When the water has all run out, slip off the 
rubber tube, sink the aspirator-bottle into the pneumatic 
tank, light the gas at the end of the glass delivery tube, 
and press the bottle down into the water. 

For the preparation of acetylene by means of electricity, 
see Sect. 257. 

If illuminating-gas is not accessible, use the process by 
electricity, or the following: 

Place in a small porcelain crucible a piece of crude tallow 
or lard as large as a walnut. Heat as suddenly and in- 
tensely as possible. In a short time the escaping gas can 
be ignited. A small Hessian crucible may be used if it is 
strongly heated before dropping in the lard. 

124. Illuminating-Gas. — The following experiment, illus- 
trative of the properties of illuminating-gas and of several 
of its waste products, may profitably be performed. / is 
a stoppered receiver of a pint capacity, made as described 
in Sect. 38. The gas, collected over water, is readily tested 
by opening the stop-cock g, sinking the receiver deep in the 
water of the pneumatic tank and applying a match. In 
transferring the receiver from the nappie e to the pneu- 
matic tank, place a large cover-glass under the mouth of /. 
The retort a is one-third filled with fine soft coal, and 



CARBON AND ITS COMPOUNDS. 69 

should be heated strongly, with caution at first. The mass 
will swell considerably in heating. In b, a one-stoppered 
receiver, the water and tar will condense. In the U-tube c 
moistened red litmus-paper is placed to detect the presence 
of ammonia. In d are strips of paper wet in a solution of 
lead acetate, which will be blackened by sulphur compounds. 
The several joints must be made very tight. 

As the experiment is quite apt to ruin a, it is a matter 
of economy to use a small retort, or substitute for it a flask 
or large test-tube properly fitted up. Spirits of turpentine 
are useful in cleaning the tar from b at the close of the 
experiment. 

A similar experiment is to fit a test-tube or ignition tube 
with cork and glass delivery tube, drawn to a jet, and heat 
soft coal in it. The gas will burn, and paper moistened 
with lead acetate solution, and red litmus-paper, if moist, 
will give characteristic tests in the unlighted stream of gas. 

125. Carbon Dioxide. — It is best prepared, as described 
in all text-books, by the action of H CI on bits of marble 
in a hydrogen generator. Pour in water enough to cover 
the end of the thistle-tube and add successive quantities 
of the acid, not more than a few spoonfuls at a time. 

126. Properties of Carbon Dioxide, (a) Its Weight. — 
Fasten small " Christmas tapers " to wires two, four, and 
six inches long. Bore holes in a piece of board and set 
up the wires vertically on it, at such a distance from each 
other that they can be covered by an open receiver or tall 
pasteboard box, like a hat-box, with the bottom cut out 
in such a way that a narrow rim is left by which the box 
may be nailed to the board. Light the taper and pass the 
delivery tube to the bottom of the receiver or box. (In 
pouring C 2 from one jar to another place the edge of the 
full bottle against the outer rim of the other. Without 
this precaution much of the heavy gas will tumble outside 
the jar.) 



70 



ELEMENTARY CHEMICAL TECHNICS. 



( b ) Absorption by Water. — Fill a test-tube, whose mouth 
is of the right size to be covered readily with the thumb, 
with C 2 . Collect the gas by upward displacement of air. 
Introduce an inch of water. Cover the mouth of the tube 
closely with the thumb and shake well. Place the tube in 
water, remove the finger, and note the ascent of the water. 
Replace the finger before raising the tube in the water, in 
order to retain all the liquid that has entered. By repeat- 
ing this, all the gas may be absorbed and the tube nearly 
filled with water. 

(c) Acid Nature when dissolved in Water. — Run the 
gas into a solution of blue litmus, or hold moistened blue 
litmus-paper in a stream of the gas. 

Fill a test-tube with C0 2 . Close it securely with the 
thumb, slip in a piece of caustic potash or soda, and add a 
few drops of water with a dropping-tube. Shake well (note 
the heat) and invert over water as in b. 

127. Its Decomposition. (a) By Metallic Sodium or 

Potassium. — Attach to the 
generator a bulb-tube, as in 
the figure. In the bulb b 
place a bright piece of so- 
dium or potassium as large 
as a pea. When the gas 
is passing through the tube 
abundantly (which can be as- 
certained by running it into 
a beaker of lime-water at d), 
heat the bulb b moderately. 
The sodium will decompose 
the C 2 . Particles of C will 
be deposited in the bulb, and 
may be washed from the resi- 
due. The experiment will fail, if by any delay a consider- 
able film of oxide gathers on the metal before heating. 



T 







no. ii. 



CARBON AND ITS COMPOUNDS. 71 

(b) By Magnesium. — Pill a large jar with C 2 . Select 
a piece of magnesium ribbon long enough to reach nearly 
to the bottom of the jar. Make an incision in the under 
surface of a cork which fits the jar, and insert the end of 
the ribbon. Get the ribbon well to burning, lower it into 
the jar and press in the cork firmly. The bits of carbon 
cannot be washed from the insoluble oxide, as in the pre- 
ceding. Therefore pour in a little water, rinse it around 
in the jar well, and pour into an evaporating-pan. Add a 
few drops of H CI, and heat a very little. A soluble 
chloride will be formed, and the tiny bits of carbon will 
float upon the clear liquid. If the combustion of the rib- 
bon is imperfect, the larger pieces of blackened metal may 
be separated by pouring the residue into a conical glass, 
allowing it to settle, and decanting the top of the liquid 
into the evaporating-pan. 

(c) By the Action of the Leaves of growing Plants. — 
Dissolve as much C 2 as possible in two quarts of water 
by letting the gas bubble through cold water for ten or 
fifteen minutes. Cut the bottom from an olive-oil bottle. 
Cork it tightly, fill it with the water, and invert it over a 
small vessel of the same water. Insert a vigorous shoot 
of a growing plant, — marguerite and mint are among the 
best, — and set the apparatus in the sunlight for several 
hours. To test the collected gas, remove the apparatus to 
the pneumatic tank. Press the bottle down into the water 
and remove the stopper. 

128. Carbon Dioxide Produced by Fermentation. — By 
adding fresh yeast to a sweet solution of molasses or 
syrup-and-water, and leaving in a warm place for 12 hours. 

129. Combustion. — The different portions of a candle- 
flame become more prominent by placing a dark body 
behind the lighted candle. 

(a) To draiv the gas from the centre of a candle, use 



72 ELEMENTARY AND CHEMICAL TECHNICS. 

a very small glass tube, No. 7, five inches long, not drawn 
to a jet. Fasten the tube in the retort-stand at an angle 
of 30° from a vertical, and adjust the flame to the lower 
end of the tube. 

(b) Or prepare a very small aspirator-bottle, not larger 
than a four-ounce, with an inlet-tube of No. 7, bent at right- 
angles. Insert the end of this tube in the blue cone of the 
flame, and let out the water slowly. To burn the gas press 
the bottle, with the outlet open, deep into a vessel of water, 
and apply a match to the end of the inlet-tube. 

(c) Blow out a candle-flame suddenly. The uncon- 
sumed gas will ascend with the smoke. Hold a flame in 
the stream. 

(d) To show that there is no combustion at the centre 
of the flame, soak a thick piece of white paper in a strong 
solution of alum. When it is dry press it squarely down 
upon the flame and suddenly remove. 

Capillary Action in the Wick. — Pass a piece of old 
grape-vine, or, better, rattan, two inches in length through 
the loosely fitting cork of a small phial. Place a very 
little ether in the phial. See that the end of the rattan 
dips beneath the liquid, and in a moment apply a flame to 
the top of the rattan. 

130. Proof that the Products of Combustion are Water 
and Carbon Dioxide. — Use a portion of the apparatus 
represented in Fig. 20. Place the U-tube d, empty and dry 
inside, in a beaker of cold water. Fill the bend of c with 
lime-water. Fasten a small tin funnel in an inverted posi- 
tion in a burette-holder, and connect the little end of the 
funnel by rubber tubing with h. Place a lighted candle 
under the funnel and draw the products of its combustion 
through the U-tubes by means of an aspirator attached at k. 
The lime-water will very quickly become milky. It will 
be necessary to continue the action for some time to con- 



CARBON AND ITS COMPOUNDS. 



73 



dense a perceptible amount of water in d. For the means 
of obtaining a constant and steady draught, see latter part 
of Sect. 30. Water will always condense on the inside of 
a cold tumbler when it is inverted over a flame. 

131. Illuminating 1 Power of Flame Due to Carbon. — Use 
the apparatus represented in Fig. 21. In place of c d use 
a tube drawn to a jet at d, and turned upward. In a gen- 
erate hydrogen. In the bulb b place a little spirits of 
turpentine. Note the luminous nature of the flame when 
the gas is ignited at d. Or sprinkle charcoal-dust in an 
hydrogen flame. 

132. Increased Weight of the Products of Combustion 
from Combining with Oxygen of the Air. — To the 
base of a large lamp chimney fit a cork. Bore 
several holes in the cork for the admission of air, 
and fasten a short piece of candle to its centre. 
Fit another cork to the top of the chimney. 

Through this cork pass a 
tube of No. 4 glass, and 
attach a four-inch U-tube, 
as in the figure. Turn a 
screw-eye e into this cork 
at such a point as to coun- 
terbalance the U-tube, and 
make the chimney hang 
vertically. Fill the tube b 
with bits of caustic-soda. 
Then exactly balance the 
whole apparatus on one 
arm of a delicate pair of 
scales. Light the candle, 
hang the apparatus upon a 
retort-stand, and with an 
aspirator connected at d draw the products of combustion 




74 ELEMENTARY CHEMICAL TECHNICS. 

into b. The caustic-soda will retain both products. After 
a few minutes remove the aspirator and return the appa- 
ratus to the scales. It will be heavier. This is an easy- 
experiment to make succeed if two precautions are ob- 
served. First, that no melted wax be allowed to drop out 
of the chimney, and second, that a constant and steady 
draught be kept up so that the waste products shall not de- 
scend upon the flame and extinguish it. To do this, make 
an aspirator of several gallons capacity from a tin milk- 
can, or, better, use the blast-pipe described in Sect. 30, 
connecting d by means of rubber tubing with the side tube 
a of the blast-pipe, Fig. 7. 

133. Preparation of Carbon Monoxide. — Heat together 
in a flask one part of powdered potassium ferrocyanide, and 
ten times its weight of strong H 2 S0 4 . Three circum- 
stances conspire to make this a troublesome experiment. 
The mass swells up and froths over if heated intensely too 
suddenly. Heat it gradually to the boiling-point. The gas 
is apt to come off with a rush at the last. As soon as the 
contents of the flask reach the boiling-point lessen the heat 
a little. Finally the gas is a little soluble in water, and its 
absorption may make a partial vacuum in the flask. Avoid 
this danger by inserting a safety tube (see Sect. 49). The 
following is a rather easier method. In a large test-tube 
fitted with a cork and glass jet-tube four inches in length 
place a teaspoonful of crystals of oxalic acid. Cover it 
with strong H a S 4 . Hold the test-tube at an angle of 45° 
and heat moderately. When the gas begins to come off, 
light the jet. Thrust the burning jet into a small-necked 
bottle and note the absence of moisture. Put a little lime- 
water into the bottle and shake. 

If desired, a greater quantity of materials may be used, 
a delivery tube substituted for the jet-tube, and the gas 
collected over water. The gas will be contaminated with 



CARBON AND ITS COMPOUNDS. 75 

some of the dioxide, which can be removed by running the 
gas through a wash-bottle containing a solution of caustic 
soda. 

134. Formation of the Dioxide from the Monoxide. — 
Fill a jar over water two-thirds full of C and the re- 
maining space with 0. Turn it mouth upward and apply 
a flame. A slight explosion will occur. 

135. Preparation of Cyanogen. — Heat some crystals of 
yellow prussiate of potash till they are dry. Mix equal 
weights of this and corrosive sublimate, and place in a test- 
tube fitted up as in Sect. 133, last part, and heat. Ignite 
the gas as soon as it begins to come off. Perform all 
experiments with carbon monoxide and cj^anogen under the 
hood, and clean the test-tubes used with great caution, as 
the gases and residues are exceedingly poisonous. 



CHAPTEE IX. 



SULPHUR, PHOSPHORUS, ARSENIC, ANTIMONY, BORON, 
SILICON, AND THEIR COMPOUNDS. 



136. To form Octohedral Crystals. — Upon about half a 
teaspoonful of flowers of sulphur in a test-tube pour twice 
its volume of C S 2 . Cork the tube and shake occasionally. 
The S will not all dissolve, as a portion is likely to be of 
a variety insoluble in the disulphide. Filter the liquid as 
quickly as possible through a single thickness of perfectly 
dry filter-paper and expose in a shallow dish for evapora- 
tion. 

137. Prismatic Crystals. — Heat bits of roll sulphur, not 
flowers, in a clay pipe-bowl. Heat gently just to the melt- 
ing-point of the entire mass. Allow a thin crust to form 
in cooling, then break the crust and pour off the liquid 
below. If a large quantity of sulphur is melted it gives 
much better results. Use a very small flower-pot, pre- 
viously closing the hole in the bottom with a plug of 
plaster-paris, and allowing the plug to dry thoroughly. 

138. Plastic Sulphur. — Prepare it as directed in all text- 
books. Use a large test-tube, and place a cork loosely in 
the mouth of the tube to keep out the air and prevent the 
sulphur from taking fire. The contents are ready to pour 
after they have passed from the viscid to a thin liquid state. 
Pour in a fine stream into cold water and skim the residue 
from the surface of the water before taking out the plastic 
mass, which will have sunk to the bottom. 

76 



COMPOUNDS. 77 

139. Preparation of Sulphuretted Hydrogen. — It is pre- 
pared in a manner identical with that of hydrogen. Use 
HC1 in preference to any other acid. The same precau- 
tions as for H must be observed in kindling the gas. The 
same lumps of iron sulphide may be used repeatedly, if 
the generator is taken to pieces immediately after using 
and the acid thoroughly washed away from them with 
clean water. 

140. Decomposition of H 2 S. — Use the apparatus shown 
in Fig. 21. A straight tube is equally as good as the bulb 
tube. Turn c d upward. As soon as the gas is ascertained 
to be free from air, heat the tube b gently in the middle. 
S will be deposited in b, and H escape at d, and may be 
kindled if desired. 

141. Brilliant Sulphide Solutions may be made by filling 
test-tubes half full of aqueous solutions of lead acetate, 
tartar emetic, silver nitrate, copper sulphate, arsenious acid 
or arsenic chloride, and zinc sulphate, and running the gas 
into each. If any fail to form the precipitate immediately, 
add two or three drops of H CI, shake, and pass in more 
gas. 

142. Sulphuretted Hydrogen Water is formed by running 
the gas into cold water. Hot water will dissolve compara- 
tively but a small quantity. 

143. Hydrogen Disulphide. — Boil together 2 grammes of 
slaked lime, 4 of flowers of S, and 32 cc. of water. When 
the liquid becomes clear suffer it to cool, then pour into 
H CI, diluted, 2 volumes. 

144. Lac Sulphuris. — When the boiling liquid in the 
above assumes the color of -gum shellac, pour off a portion 
into a test-tube, and after it is cool add a little H CI, di- 
luted, 2 volumes. Or boil together 1 gram of slaked lime, 
2 of flowers of S, and 25 cc. of water, till the brown color 
appears. Then cool and add the dilute acid. 



78 ELEMENTARY CHEMICAL TECHNICS. 

145. Sulphur Dioxide. — The gas contaminated with N 
may be made by merely burning S in a deflagrating-spoon 
in a fruit-jar, covering the jar loosely. It can be obtained 
in a pure state by treating copper or iron-filings or mer- 
cury with H 2 S 4 (the first is best). Place the filings and 
strong H 2 S0 4 enough to cover them in an 8-ounce flask 
provided with cork and delivery tube. Heat gently and 
cautiously, lessening the heat whenever the mass shows a 
tendency to swell up and froth over. The gas is evolved 
most freely just at the boiling-point. Collect by upward 
displacement of air. 

146. Condensation of Sulphur Dioxide to a Liquid. — 
By means of a rubber connector 8 or 10 inches in length, 
attach a three-inch U-tube (fitted up with corks and deliv- 
ery tubes bent at right angles in each arm) to the delivery 
tube of the flask prepared for the generation of S 2 . Set 
up the flask ready for heating. Place the U-tube in a 
conical measuring-glass and pack it round with a freezing 
mixture of pounded ice and coarse salt. To the limb of 
the U-tube, not connected with the flask, attach a piece 
of rubber tubing and carry the tubing into a bottle of cold 
water in order that the excess of gas may be dissolved 
instead of escaping into the room. Note the action of the 
liquid S 2 when poured upon water. 

147. Bleaching Action of Sulphur Dioxide. — To show 
the bleaching action of S0 2 , get a piece of roll S well to 
burning on a piece of broken crockery laid on a plate. Set 
a vase containing red roses, pansies, or oxalis flowers, 
previously dipped into water, on the plate and invert a 
bell-jar over both burning sulphur and vase of flowers. 

148. The Preparation of the Troxide is difficult for an 
ordinary school experiment. 

149. Preparation of Sulphuric Acid. — Besides the usual 
text-book experiment the following simple illustration of 



COMPOUNDS. 79 

the formation of H 2 S 4 may l?e given. Burn a piece of 
roll S in a quart jar. (The S may be made to ignite more 
readily by turning 3 or 4 drops of alcohol over it.) Then 
stir the contents of the jar about with a swab wet in 
HiSTC^. Pour in a few drops of water and shake. The 
water will then give an acid test with litmus-paper, and 
the addition of a solution of barium chloride shows the 
acid to be H 2 S 4 . 

150. Additional Experiments with H 2 S 4 . — (a) Fill a 
narrow test-tube one-third full of strong acid. Mark the 
level with a string tied about the tube and leave exposed 
to the air a few days. 

(b) Prepare a strong syrup by dissolving sugar in water. 
Add an equal volume of strong acid, and stir. 

(c) Write upon white paper with a glass rod dipped in 
the acid, diluted one volume. Dry the paper at the lamp, 
holding the paper as near as will be safe. 



PHOSPHORUS. 

151. Precautions in regard to Handling. — Always cut 
and scrape phosphorus under water in a lead pan or saucer. 
It cannot be handled with safety, for the warmth of the 
hands is likely to set it on fire. If it is burned when 
the surface is wet the burning fragments are thrown about 
much more violently. Therefore always gently wipe with- 
out any friction upon soft paper all pieces intended to be 
burned. Keep bottles containing phosphorus well filled 
with water, and in a place where the water cannot freeze. 
Remember that it is a violent poison when taken into the 
stomach in the minutest quantities. For the treatment of 
its burns, see Sect. 59. 

152. Preparation of Red Phosphorus. — Many dealers in 



80 ELEMENTARY CHEMICAL TECHNICS. 

chemicals do not keep red phosphorus. It can be prepared 
when needed. Use the apparatus shown in Fig. 21. The 
red phosphorus can be removed more easily if a straight 
tube one inch in diameter is substituted for the bulb tube. 
In b, or the straight tube substituted, place several small 
pieces of P. Let d be drawn to a jet-point to insure the 
exclusion of the air. Generate C 2 in the usual manner 
in the generator to expel the air. When the tube is cer- 
tainly clear of air, carefully heat the tube under the pieces 
of P. The vapors, as they escape from d, will burn spon- 
taneously. Avoid heating sufficiently for the melted phos- 
phorus to boil, as it will then be reconverted. Continue 
to evolve the C0 2 till the apparatus is cooled below the 
kindling-point of the element. 

153. Spontaneous Combustion of Phosphorus. — To cause 
P to ignite spontaneously with the absorbed in charcoal, 
place the P on a non-conducting surface like thick blotting- 
paper, and cover to about the depth of £ of an inch with 
finely pulverized bone-black. It will burst into flame in 
from 1 to 3 minutes. 

Phosphorus dissolved in CS 2 , and poured over a sheet 
of filter-paper, will burst into flame spontaneously as soon 
as the C S 2 is fairly evaporated. 

154. The Phosphine Rings Experiment is quite fully de- 
scribed in most text-books. Make the caustic solution by 
dissolving 20 grammes of caustic potash in 60 cc. of water. 
A cheaper solution, that will do nearly as well, is made 
by mixing 30 grammes of air-slaked lime with 100 cc. of 
water. Before inserting the cork and delivery tube into 
the flask pour in four or five drops of ether to expel the 
air. The gas is evolved best when the liquid boils vigor- 
ously. Keep the end of the tube scrupulously under the 
water in the pan. When the rings begin to come off, all 
currents from windows and doors, or the movements of 






COMPOUNDS. 81 

pupils, must be avoided. The experiment should be con- 
tinued but a short time ; the entire apparatus should be set 
outside the room or under the hood, and the room thor- 
oughly ventilated as soon as possible, as the products are 
quite harmful. 

155. Phosphoric Anhydride may be easily made. Thor- 
oughly dry and heat hotter than can be conveniently held 
in the hand, at a furnace or coal-stove, a common plate and 
two-quart jar. Place a piece of P twice as large as a pea 
upon the plate. Ignite and invert the jar over it, leaving 
one side canted up for the free admission of air. The 
flaky white powder will gather upon the sides of the jar 
and in the plate. 

Phosphoric Acid. — Scrape the powder into a mass and 
add a few drops of water. It dissolves surprisingly rap- 
idly, and a little evaporation produces the syrupy phos- 
phoric acid. 

Note the gyratory movement when flakes of the P 2 6 are 
thrown upon water. 

156. Hypophosphorous Acid may be made with some diffi- 
culty. Make a solution of barium hydrate. Place it in a 
flask and add three or four small pieces of P and a few 
drops of ether. Boil for some minutes. Filter and add 
cautiously dilute H 2 S 4 . 

157. The Preparation of Trioxide and Phosphorous Acids 
are too troublesome to be attempted with ordinary appli- 
ances. 

ARSENIC. 

Do all heating of oxides and other compounds of As 
under the hood, as the vapors, if inhaled, sometimes pro- 
duce nausea, and occasionally serious illness. 

158. Arsine and Marsh's Test. — Great caution should 



82 ELEMENTARY CHEMICAL TECHNICS. 

be exercised in preparing hydrogen arsenide, and in show- 
ing the Marsh's test, as the gas, even in an impure state, is 
intensely poisonous. Generate hydrogen in the usual man- 
ner in a generator provided with a glass delivery tube, 8 
or 10 inches long, bent with one right angle, and drawn to 
a fine jet at the end. With the usual precautions ignite 
the gas. Dissolve a little white arsenic in water, or, better, 
H CI. When the flame is burning steadily pour not more 
than three or four drops of the arsenic solution into the 
thistle-tube and rinse it down with H CI. Bo not let the 
flow of gas slacken, or the flame on any account become 
extinguished. When the tests have been satisfactorily 
made the flame should be extinguished and the apparatus 
immediately taken to pieces and thoroughly rinsed. Do 
this without fail under the hood or out of doors. 

Test carefully with the cold porcelain before putting in 
the arsenical solution, for the zinc may contain arsenic 
enough to give the test. 

159. Wall-papers may be Tested for arsenic by soaking 
the paper for some time in warm water acidulated with 
H CI. Add a teaspoonful of this at a time to the generator, 
and at the same time additional H CI, and apply the porce- 
lain test. 

Add to the solution of wall-paper a drop of ammonia. 
A blue tint is evidence of the presence of a copper salt 
with which salts of arsenic are apt to be associated. If 
there are green spots in the paper, drop ammonia upon 
them and note if they turn blue. 

160. Silver Nitrate Test of Arsenic. — In addition to 
the porcelain-mirror test an interesting test may be made 
if the precaution is taken to make the delivery tube in 
three parts : first, the tubing bent at right angles passing 
out of the bottle ; second, a piece of rubber tubing, three 
or four inches long, to form a flexible joint ; and third, a 



COMPOUNDS. 83 

piece of glass tubing, two inches long, drawn to a jet-point. 
Pass the jet-tube, still ignited, down into a dilute solution 
of silver nitrate in a test-tube. A black precipitate of 
silver will presently form. 

161. Scheele's Green. — Make a solution of copper sul- 
phate and add ammonia till the precipitate redissolves. 
Prepare a solution of arsenic trioxide in dilute H CI. Pour 
some of the sulphate solution into a test-tube and add a 
little of the arsenic solution. Then add successive quanti- 
ties of each solution till the proper relation of acid and 
alkali is established. 

162. Sulphide of Arsenic. — Dissolve white arsenic in 
water and add H 2 S. The bright yellow sulphide will be 
precipitated. 

163. Combustion of Arsenic. — Metallic As will burn 
brilliantly in 0. Set it on fire in a deflagrating-spoon and 
lower into a jar of 0. 

164. For decomposition of As 2 3 by metallic copper, see 
Sect. 260. 

ANTIMONY. 



165. Antimony Chloride. — The preparation of " anti- 
mony butter " is sometimes quite troublesome. Fulfil care- 
fully these conditions : The H CI must be strong ; the Sb 
pulverized very fine ; the ratios of materials exact (say half 
a gramme or 8 grains of. antimony, and 2 ounces or 60 cc. of 
H CI). Before beginning to boil add 8 drops (not more nor 
less to the quantity of metal and acid given) of H Y 3 . 

166. Antimony Mirror. — To form the antimony mirror 
on cold porcelain proceed in a manner identical with that 
employed in obtaining the arsenical mirror. Pour into the 
generator a few drops of a solution of tartar emetic, or a 



84 ELEMENTARY CHEMICAL TECHNICS. 

very little butter of antimony, and wash it down the tube 
with H CI. Then place the porcelain in the flame. An 
arsenical mirror can be washed away with a solution of 
sodium hyposulphite; the antimony stain cannot. Com- 
mercial antimony is quite apt to contain traces of As, and 
thus confuse the test if antimony chloride is used. The 
gas is not as dangerous to inhale as arsine. 

167. For the decomposition of salts of Sb by a weak 
current, see Sect. 261. 

BORON. 



168. Borax Beads. — In working with the " borax bead " 
use a small platinum-wire, about inches in length. Make 
the surface perfectly clean. Form the loop by bending the 
wire around some cylinder not larger than a good-sized 
knitting-needle. When the bead is hot let it come in con- 
tact only with the minutest quantity of the compound to be 
tested. 

169. Boracic Acid. — Crystals of boracic acid are formed 
by dissolving borax in boiling water nearly to saturation 
(10 cc. of water, 5 grammes of borax) and adding strong 
H 2 S 4 or H CI (cautiously with the mouth of the test-tube 
averted from the face) to the hot solution. As the liquid 
cools, the crystals will appear. 

SILICON. 

170. Preparation of Silicon Fluoride. — Obtain silicon, 
fluoride as directed in all text-books, by heating together 
fine sand, powdered fluorspar, and strong H 2 S 4 . The gas 
is usually passed into water. The jelly-like silicic acid 



COMPOUNDS. 85 

will clog the delivery tube. Obviate this in either of two 
ways. Let the delivery tube be wholly of glass, and bent 
twice at right angles so that the last section shall pass 
straight down into the water. Then, either place the 
water in a conical glass and pour mercury into the bottom 
sufficient to cover the amount of the delivery tube, or select 
a piece of tubing, one-half to an inch in diameter and two 
inches in length, and fit a cork with a small delivery tube 
to it. Pass this little delivery tube through a second cork 
which fits the tube from the flask, and insert this cork into 
the delivery tube of the flask, which will thus have a large 
calibre where it dips into the water. The jelly, as it 
gathers in the tube, can then be readily scraped out with 
the handle of a teaspoon, and clogging prevented. 

171. Dialyzer. — A convenient dialyzer is made by cut- 
ting off a round wide-mouthed pint bottle about half-way up 
from the bottom, and stretching a piece of hog's or beef's 
bladder over the opening and tying it securely around the 
neck. Place the liquid to be dialyzed in the bottle and 
suspend it in two quarts or more of pure water. Several 
days are necessary for the complete dialysis of silicic acid. 



CHAPTEE X. 

THE METALS. 

172. Alkali Metals. — For the spectrum analysis of com- 
pounds of these metals, see Chap. XI. 

SODIUM AND POTASSIUM. 

Sodium and potassium must be kept under naphtha in 
very tight bottles, must never be left exposed to the air, 
or handled with wet fingers. 

173. Decomposition of Water by Sodium. — When it is 
desired to collect hydrogen from water by means of so- 
dium, roll up a piece of wire-netting, four or five inches 
square, around a test-tube or some cylindrical body. Bend 
down one end of this hollow cylinder and it constitutes 
a wire cage. Insert the sodium, and, nipping up the other 
end of the cage with a pair of pincers or crucible tongs, 
hold it under the mouth of the collecting bottle, filled with 
water, which is inverted in a basin of water. 

174. Protection from flying Pieces of Metal. — When 
pieces of either sodium or potassium are thrown upon 
water, care should be taken to protect the hands and eyes 
from flying bits of metal, as the metallic globule is apt to 
explode violently at the last. The water can be placed in 
a wide-mouthed bottle, and a cover-glass slipped over the 
top as soon as the metal is dropped in. Or the hands may 

86 



THE METALS. 87 

be encased in gloves and the face averted sufficiently to 
avoid danger to the eyes. 

Sodium will inflame spontaneously only upon hot water. 

175. Combustion in Oxygen. — Na and K will burn 
brilliantly in 0. Heat very small pieces of the metals to 
redness in the wire cage mentioned above, and lower into 
a jar of 0. 

176. Melting in an Atmosphere of Hydrogen. — Both 
metals can be melted by using the apparatus shown in 
Fig. 21. Generate hydrogen, and when the gas is pure 
and abundant, insert a piece of the metal into the bulb 
tube and attach it to the delivery tube of the generator. 
After a minute or two heat the bulb cautiously. The 
silvery metallic nature of sodium is beautifully shown in 
the molten globule. When potassium is heated, a beauti- 
ful green vapor forms, which will burn spontaneously and 
harmlessly at d, making a very brilliant experiment. The 
bulb tube must be perfectly dry. It is well to insert a 
drying tube of calcium chloride between the generator and 
the bulb tube. 

177. Combustion in Chlorine. — Both metals burn bril- 
liantly in CI gas. Lower tiny bits of the metals into jars 
of the gas. The K will take fire in a cold condition if it is 
placed in the jar before a heavy film of the oxide has time 
to form. In the case of Na it will be necessary to heat 
the metal in the deflagrating-spoon. It is well to protect 
the hand by means of a piece of pasteboard cut out a little 
larger than the mouth of the jar. Thrust the handle of 
the spoon up through the pasteboard, so that the latter 
shall cover the mouth of the jar when the spoon is lowered 
into it. 

178. Additional Experiments. — (a) Color water with red 
litmus or purple cabbage solution, and throw a piece of K 
upon it. 



88 ELEMENTARY CHEMICAL TECHNICS. 

(b) Cover the bottom of a small-necked half-pint bottle 
with bromine. Drop a minute piece of K into it from a 
deflagrating-spoon held at arm's length. 

( c ) Place a tiny flake of iodine and a thin slice of K 
in contact on a piece of tin placed on a ring of the retort- 
stand and invert a tumbler over the chemicals. Heat the 
tin slightly. 

AMMONIUM. 

179. Ammonium Amalgam. — Place 3 or 4 cc. of sodium 
amalgam (for the preparation of the amalgam, see Sect. 199) 
in a large measuring-glass, and pour over it a strong solu- 
tion of ammonium chloride made by dissolving about 12 
grammes of the chloride in 40 cc. of water. The mass 
makes an astonishing increase in bulk. Note the rapid 
decomposition of the amalgam when exposed to the air. 

180. Prepare Ammonium Hydrosulphide by running H 2 S 
gas for several minutes into strong ammonia water, passing 
the delivery tube of the gas nearly to the bottom of a test- 
tube two-thirds filled with ammonia. 

A few drops of this hydrosulphide added to weak soul- 
tions of sulphate of zinc, copper, and iron, and to tartar 
emetic, will produce beautiful precipitates. 



CALCIUM, STRONTIUM, AND BARIUM. 

181. Decomposition of Calcium Carbonate. — The forma- 
tion of " quicklime " from the carbonate is readily shown 
by placing a bit of marble on a piece of charcoal and 
directing the blowpipe flame against it. 

182. Strontium and Barium Salts in Pyrotechny. — Illus- 



THE METALS. 89 

trate the use of strontium and barium salts in pyrotechny 
as follows : Weigh out, accurately, 2 parts of strontium 
nitrate, 2 of potassium chlorate, and 1 of gum shellac. 
Pulverize them separately and very fine, and mix them 
thoroughly, but very cautiously, with a horn spatula or 
piece of pasteboard. Prepare a second mixture in the 
same manner as the first, using in place of the strontium 
nitrate the same proportion of barium nitrate. Burn a 
little at a time in an iron mortar, Hessian crucible, or on 
a brick. The former mixture yields red fire, the latter 
green. 

183. Blanc Fixe. — Barium nitrate treated with H 2 S 4 
yields "blanc fixe." 

184. Preparation of Barium Peroxide. — It is important 
to prepare barium dioxide if it is desired to make hydrogen 
dioxide, as directed in Chap. V., Sect. 75. 

Pulverize 2 grammes of barium oxide and mix with about 
2\ grammes of potassium chlorate. Heat the mixture in a 
small crucible till the oxide burns feebly but completely in 
the oxygen of the chlorate. Then let the mass cool and 
place in a close-stoppered bottle, if not immediately used. 
Select such a bottle that the dioxide will fill it, and if the 
stopper is not very tight, melt in wax about it. 



SILVER. 

185. Coin Solutions. — Use old-fashioned three and five 
cent pieces, if they can be obtained, for making solutions 
of silver coins. 

186. The Action of Light upon Silver Salts is readily 
shown by adding sodium chloride, potassium iodide, and 
potassium bromide to solutions of silver nitrate, and ex- 
posing the precipitates to the sunlight. 



90 ELEMENTARY CHEMICAL TECHNICS. 

187. Illustrate the Principle of Photography as follows. 
Cut out a piece of white paper the size of a cover-glass. 
Soak the paper in a solution of silver nitrate and allow it 
to dry in a dark place. Cut out a piece of pasteboard of 
the same size and remove a rectangle from the centre in 
such a way that the pasteboard shall resemble a picture- 
frame about a quarter of an inch deep. Place this frame 
over the glass, and the sensitive paper under it. Then place 
upon the frame a transparent lantern-slide, or if that is not 
at hand, a piece of lace, and bind all securely into place 
with thread. This can then be set in the sun to " print." 
The "tone" can be watched from the back side of the 
paper. 

188. For the formation of the Silver Tree, see Sect. 260. 

189. For the Action of Mercury upon a Nitrate Solution, 
see Sect. 2G0. 

190. Explosiveness of Nitrate with Phosphorus. — Like 
potassium chlorate, silver nitrate will explode with a loud 
detonation if wrapped in paper with a bit of phosphorus 
and struck upon a brick with a hammer. Use only a very 
minute quantity of each substance. 

191. Combustion of Nitrate with Charcoal. — Finely 
powdered nitrate and charcoal in the same condition, 
mixed, five parts of the salt to one of charcoal will defla- 
grate quite brilliantly when set on fire, leaving metallic 
silver. 

192. Silver Oxide. — Potassium hydrate added to a dilute 
nitrate solution will produce a copious precipitate of silver 
oxide which ammonia dissolves out, leaving the liquid sur- 
prisingly limpid. 

193. Silver Mirror. — A silver nitrate solution heated 
in a test-tube with tartaric acid leaves a silver mirror on 
the side of the tube. 



THE METALS. 91 



ZINC. 

194. Combustion of Zinc. — If zinc-filings and fine po- 
tassium uitrate are thrown into an intensely hot crucible, 
the zinc will burn brilliantly, producing " philosopher's 
wool." Drop the substances into the crucible from a long- 
handled spoon or deflagrating-spoon, standing away at arm's 
length. • 

195. For the formation of Granulated Zinc, see Sect. 58. 



MAGNESIUM. 

196. The Action of Magnesium in decomposing carbon 
dioxide was shown in Sect. 127, b. 



ALLUMINUM. 

197. Formation of a "Lake." — Prepare a strong decoc- 
tion of cochineal by macerating a few grains in a mortar 
with a few drops of cold water, and boiling this pulpy 
mass in 75 cc. of water. Filter and pour into a tall 
measuring-glass or a large test-tube and add an equal vol- 
ume of a strong solution of alum. Strong ammonia will 
then precipitate " purple lake," which may be separated by 
filtering. 

MERCURY. 

198. Precautions in working with Kg and its Salts. — 

Mercury will destroy articles of gold jewelry by forming 



92 ELEMENTAL Y CHEMICAL TECHNICS. 

an amalgam with them. Kings should always be removed 
when working with this element. The vapors of mercury- 
are poisonous, and must be scrupulously avoided. The salts 
are also extremely poisonous when taken into the system. 

199. Prepare "Sodium Amalgam" as follows: Place 
5 cc. of mercury in a flask. Warm the mercury a very 
little, either out of doors or under the hood, and drop in 
successively about 20 pieces of sodium, none of them much 
larger than a pin-head. 

200. For the Separation of the Metal from the Chloride 
by a weak current of electricity, see Sect. 260. 

201. Examination of Mercuric Iodide with the Micro- 
scope. — Make solutions of mercuric chloride, 10 grains of 
the salt in 15 cc. of water; and of potassium iodide, 12 
grains of the salt in 15 cc. of water, and mix. A precipi- 
tate yellow, changing to red, will form. Warm a glass 
microscope slide, with a pinch of the red salt upon it, till 
the color changes to yellow. Then examine the salt, as the 
slide cools, under a compound microscope, using about an 
one-inch objective. Illuminate the object from above with 
the concave mirror or bulls-eye condenser. It makes an 
extremely beautiful object for the microscope. 

202. Explosiveness of the Oxide with P. — The red oxide 
and a bit of phosphorus wrapped in paper and placed upon 
a brick will explode violently when struck a smart blow 
with a hammer. 

203. Formation of Calomel. — Add oxalic acid to a solu- 
tion of mercuric chloride and leave exposed to direct sun- 
light for a little time. Pearly flashing scales of calomel 
will separate. 

TIN. 

204. Convenient Forms for Use in the Laboratory. — 

Chemically pure sticks and pulverized tin can be bought, 



THE METALS. 93 

both of which are very convenient. Bar and block tin are 
not pure. The most convenient salts to use are the chlo- 
ride. It is better to purchase these than prepare them. 
They may be prepared with the exercise of considerable 
care as follows : • 

205. Preparation of Tin Chloride. — Granulate a little 
tin in the same way as directed to granulate zinc (Sect. 58). 
Weigh out a gramme of this and place it in a 4-ounce flask ; 
add 6 cc. of strong HC1 and 3 drops of H]Sr0 3 and boil 
for some ten minutes. Before the metal is all dissolved, 
remove the heat, and stannous chloride will be the result. 

206. To form the Perchloride, use 12 cc. of H CI. After 
the metal is completely dissolved, remove the liquid to 
an evaporating-pan ; add 1 cc. of HN0 3 and evaporate 
half the bulk. 

207. Tin is easily separated from a Chloride Solution. 
— See Sect. 260. 

208. The White Tin Dioxide is made by covering pieces 
of tin with strong H N 3 . Perform under the hood. 



LEAD. 

209. Lead Iodide. — Add a drop or two of a solution of 
potassium iodide to one of lead nitrate, and acidulate the 
mixture with 2 or 3 drops of H CI. Beautiful yellow lead 
iodide is made. 

210. For the Formation of the "Lead Tree," see Sects. 
259 and 260. 

211. Litharge may be readily purchased. 

212. The Dioxide can be purchased or prepared from 
commercial " red lead " which is kept in stock at any paint 
store. Commercial red lead is a mixture of the protoxide 



94 ELEMENTARY CHEMICAL TECHNICS. 

and true dioxide. Pour dilute HN0 3 upon the commer- 
cial article and heat a little. The protoxide will dissolve 
out and the dioxide remain insoluble. It can then be 
separated by filtering. 

213. Lead " Pyrophorus." — Make a solution of "ro- 
chelle salts," and add a solution of lead acetate till the 
precipitate is all formed. Filter out and dry the tartrate. 
Half a teaspoonful or more of this should be made. Place 
this in an ignition tube (a test-tube is not as good, but will 
do if heated so as not to melt it) and heat to a red glow as 
long as any fumes are driven off. Before heating, select a 
sound cork that is a perfect fit for the tube and have it in 
readiness. The instant the heat is removed, insert the cork 
very firmly. The success of the experiment depends upon 
the utter exclusion of the air. It may be well, after press- 
ing in the cork very firmly, to cut it off squarely, press it 
in a little farther, and spread melted sealing-wax completely 
over the end. When thoroughly cold, break open the tube 
and pour the fine powder or " lead pyrophorous " from a 
considerable height into a nappie. Note the formation of 
litharge in the nappie. 

214. Lead Chloride. — Make a very strong solution of 
lead acetate and add H CI. Lead chloride will precipitate 
in crystals. 

BISMUTH. 

215. " Fusible Metal " is easily prepared. Melt 2 parts 
by weight of bismuth in a Hessian crucible. Then add 
one part each of lead and tin, in small portions at a time, 
stirring as they melt. Select a piece of No. 4 glass tubing, 
6 or 8 inches long, and close one end with a phial-cork. 
Place the rod in a test-tube of hot water, the closed end 






THE METALS. 95 

down, and pour into this mould the hot alloy. Then re- 
move the tube from the water. The expansion of the 
cooling metals will break the mould. This metallic rod 
placed in boiling water will soften and partly melt down. 

216. Bismuth can be Separated from the Chloride by the 
action of a zinc strip and by electrolysis. See Sects. 259 
and 261. 

217. Combustion in Chlorine. — Bismuth, finely powdered, 
burns spontaneously when dropped into CI gas. 

218. Chloride. — Hot strong HC1 will dissolve a little 
of the metal forming the chloride. Do not dilute this 
with water, as it will thus be decomposed. 



MANGANESE 

219. " Chameleon Mineral " is prepared as follows : Mix 
equal weights of Mn 2 and K CI 3 with one-fourth their 
combined weight of caustic potash. Heat intensely in a 
Hessian crucible till the mass is green. Dissolve in cold 
water. The solution, at first green, will gradually turn to 
a splendid purple. After a few days the solution will be 
filled with flakes of a beautiful color, slightly iridescent. 

220. Decomposition of the Dioxide. — The dioxide heated 
strongly in a test-tube will jdeld oxygen. 

The same oxide heated with H CI sets free chlorine, one 
method of obtaining that element. 

Heated with about two-thirds its own weight of H 2 S 4 
it yields oxygen. 

221. Spontaneous Combustion by means of the Per- 
manganate. — Pulverize a few crystals of potassium per- 
manganate and cautiously add the powder to strong H 2 S 4 . 
Make a pipette of a piece of No. 2 or 3 glass tubing, about 



96 ELEMENTARY CHEMICAL TECHNICS. 

2 feet long, by drawing one end ont to a moderately fine 
jet-point. Pour into an evaporating-pan a few drops of 
alcohol, ether, or bisulphide of carbon (the first is the best), 
and with the pipette, held in almost an horizontal position, 
insert into the pan of alcohol two or three drops of the 
permanganate solution. The alcohol will ignite sponta- 
neously. Some volatile substances burn thus quite ex- 
plosively. 

IRON. 

222. The Precipitates with Iron Salts are very inter- 
esting. 

To a solution of caustic potash add a few drops of fer- 
rous sulphate solution. 

To a solution of potassium ferrocyanide add the iron 
sulphate solution. Eepeat the experiment with ferricya- 
nide. 

Leave the precipitates of the first two exposed to the 
air for a time. The first will be reddish-brown, the second 
and third blue. 

223. Electricity will Separate Iron from its salts. See 
Sect. 259. 

224. Iron Hydroxide is a useful substance in case of 
arsenical poisoning and for other purposes. Place some 
clean iron-filings in a broad shallow dish as an evapo- 
rating-pan. Pour over them H 2 S 4 diluted with 7 or 8 
volumes of water. Use as much as 12 cc. of the dilute 
acid. Cover the pan loosely with a piece of glass to pre- 
vent too rapid evaporation, and leave over night. Then 
filter the liquid into a test-tube and add H 3 jST till the 
hydroxide is precipitated, which can be separated by filter- 
ing. To be useful as an antidote in arsenical poisoning it 
must be freshly precipitated and moist. The hydroxide 



THE METALS. 97 

can be prepared in a shorter time using stronger acid, bnt 
care must then be exercised to prevent excessive frothing 
when the acid is poured upon the filings. 

225. Sesquioxide. — Iron sulphate, when heated intensely 
in an ignition tube or crucible, is converted into the ses- 
quioxide. 

COPPER. 

226. Nature of Salts. — The salts of copper are poison- 
ous when taken into the system. 

227. Copper Dioxide. — Place a few drops of honey in 
a solution of copper sulphate and add caustic soda solution 
till the precipitate at first formed entirely redissolves. On 
standing, the red dioxide will precipitate. 

228. The Hydrated Oxide is obtained by adding an ex- 
cess of caustic potash solution to a sulphate solution. 

229. To Form the Black Protoxide, boil in separate 
test-tubes a rather dilute solution of copper sulphate and 
strong caustic soda, and pour the contents of one tube into 
the other while both are boiling hot. 

230. Protosulphide. — To a solution of the sulphate add 
2 or 3 drops of H 2 S 4 and run in sulphuretted gas. The 
protosulphide will precipitate. 

231. Chloride. — Dissolve copper oxide in H CI and evap- 
orate the solution slowly and gently. Green needle-like 
crystals of copper chloride will form. 

232. " Casselman's Green." —Place in an evaporating-pan 
some bright copper-filings and cover them with acetic acid, 
and leave over night. In the morning the acid will be 
evaporated and the bottom of the pan covered with the 
green acetate. Rinse out the pan with water and pour the 
rinsings into a test-tube, straining out the copper clippings. 
Add a few drops of ammonia, bring it to the boiling-point, 



98 ELEMENTAEY CHEMICAL TECHNICS. 

and pour into a boiling solution of tiie sulphate. The 
result is " Casselman's Green." 

233. Nitrate. — A slow evaporation of the liquid in the 
generator, after making nitric oxide, will yield crystals of 
copper nitrate. 

234. For the Separation of Copper from its Salts by 
Electricity, see Sect. 259. 



PLATINUM. 

235. Melting of Platinum. — Small platinum wire will 
readily melt in the oxyhydrogen flame. See Sect. 70. 

236. Platinum Dissolved in "Aqua Regia." — Pour over 
the metal just enough of the liquid to cover it. When 
the action ceases, pour this off into a test-tube, and add a 
fresh portion of aqua regia. Thus repeat the operation 
until the metal is entirely dissolved. For some reason 
the successive portions accomplish more than the entire 
quantity poured over the metal at once. The aqua regia 
is made by adding strong nitric acid to strong hydrochloric 
acid just at the time that it is desired to use it. 

237. Show the Oxidizing Power of Platinum upon am- 
monia and ether in the following way: Make a spiral, 
about two inches long, of rather fine platinum wire by 
winding it around a piece of No. 6 glass tubing. Suspend 
this at a convenient height from the bar of a pipette-holder 
or a ring of a retort-stand. Place a few drops of ether in 
one warm test-tube, and of strong ammonia in another. 
Place a lighted spirit-lamp under the spiral. When the 
metal is in a bright glow, remove the lamp and instantly 
place one of the tubes under the spiral and raise it so that 
the glowing metal shall be in the middle of the tube. It 



THE METALS. 99 

will continue to glow till all the vapor contents of the tube 
are oxidized. 

238. Platinum Sponge. — Dissolve platinum in aqua 
regia and boil till a yellow precipitate appears. Filter 
out this precipitate. Wrap it as closely as possible in a 
piece of tough paper making a compact pellet of it. Secure 
it by winding fine platinum wire about it. Pass a piece of 
larger platinum wire through a loop in the binding wire 
for a handle, and heat the pellet intensely till the paper is 
all burned away and the salt becomes a grayish mass. It 
makes a very convenient pellet of platinum sponge. 

Platinum chloride can be purchased, and affords a little 
easier means of obtaining the sponge. To the liquid chlo- 
ride add a strong solution of ammonium chloride. If the 
precipitate fails to appear, add a few drops of HC1. If 
there is a tendency on the part of the precipitate to redis- 
solve, pour in alcohol. Then filter and heat the precipitate 
as directed above. 

Platinum sponge that has not been used for some time 
will need to be cleansed. Heat it gently to quite an in- 
tense heat, and allow to cool before using. 



GOLD. 

239. For the Electrolysis of the Chloride and for Elec- 
troplating with Gold, see Sects. 259 and 268. 

240. The Green Color of the Light transmitted by gold 
leaf may be illustrated. Float a gold leaf upon water. 
Place a cover glass in the water under the metal and care- 
fully and squarely take up the leaf on the glass. Press 
the gold leaf down upon the plate by blowing with the 
breath directly against it till the film of water is all driven 
out and the metal adheres firmly and smoothly to the glass. 
Then hold the plate up toward the light. 



CHAPTER XI. 

SPECTRUM ANALYSIS. 

241. Kind of Spectroscope to be Used. — Accurate and 
extended investigation into the spectra of elements can 
only be made with expensive instruments. But the spectra 
of several substances are well exhibited by the use of 
simple " pocket " spectroscopes costing from ten to sixteen 
dollars. 

The work indicated in this chapter has been done with 
a " Browning's pocket spectroscope." 

242. Care of the Instrument. — The spectroscope must 
be kept scrupulously clean. Particles of dust adhering to 
the lips of the narrow slit may appear to the novice as 
strangely arranged bands running lengthwise of the spec- 
trum. 

243. To Adjust the Instrument. — For a class experi- 
ment, clamp the spectroscope into the pipette-holder in a 
horizontal position, and set the holder upon the lecture 
table at a convenient height. Cut out a square or circular 
screen of thick pasteboard, six inches in diameter. Make 
a hole of the proper size at the centre and slip it on the 
end of the spectroscope. It will afford a grateful protec- 
tion to the eyes from the glaring light. An alcohol lamp 
will vaporize most of the compounds used, but a Bunsen 
burner with a ring for closing the base draughts is much 
to be preferred. Place the burner within one or two inches 

100 



SPECTRUM ANALYSIS. 101 

of the narrow slit of the spectroscope with the draught 
adjusted for a luminous flame. By means of the ring on 
the tube adjust the narrow slit so that a clean sharply 
defined light spectrum is obtained. Then alter the flame 
to a non-luminous one. If it is necessary to use an alcohol 
lamp, set the light carbonaceous flame of a candle or kero- 
sene lamp before the instrument while adjusting for a clear 
spectrum, and when that is obtained substitute the alcohol 
flame in exactly the same position occupied by the bright 
flame. The usual method of obtaining spectra by dipping 
a piece of platinum wire in some salt, and holding it in the 
flame, is impracticable before a class. The spectrum gen- 
erally flashing out for an instant and disappearing, the 
process must be repeated a tedious number of times. 

244. Tubes for Holding Solutions. — Fig. 23 represents 
a convenient piece of apparatus that will give a steady 
colored flame and clear spectra for a long time. 
It is made of pieces of No. 3 soft glass tubing 
with one inch of their length bent at right 
angles and the ends closed with small corks. 
Through each cork is passed a kind of wick fta23, 
made as follows : Around a rather stout piece 
of platinum wire, two inches in length, are passed numerous 
fine fibres of asbestos of the same length as the wire and 
laid parallel with it. This little bundle is then secured by 
winding with very fine platinum wire. The tubes are filled 
with a solution in water of the various salts to be examined. 
The fluids work slowly through the fibres of the wicks by 
capillary action, and when the wicks are inserted in the 
flame the characteristic coloring immediately appears, and 
the spectrum can be viewed at leisure. The tubes should 
be labelled with the formula of the solution and scrupu- 
lously kept for use for that one substance. The upright 
axis b may be fastened into a pipette-holder or attached 




102 ELEMENTARY CHEMICAL TECHNICS. 

to a base of its own, made from a square piece of board, 
and adjusted to such a height as to bring each wick upon 
a level with the flame, and by revolving the little turn- 
table each solution can be easily brought into the flame. 
The standard b is made of a section of broom-handle, 7 
inches long, and terminating in a stout wire axis at the 
top. a is a disk, 6 inches in diameter, cut out of half- 
inch pine stock. The holes should be bored a trifle larger 
than the diameter of the tubes. To secure the tubes in 
place, cut a little square slot in the side of each hole and 
whittle out little wedges to fit the slots, and by pressing 
the wedge down beside the tube they are held securely in 
place. 

245. Spectra of Different Metals. — With the Bunsen 
burner the spectra of Ba, Ca, Cu, K, Li, Mn, Na, Kb, Sr, 
and several others can be very readily obtained. The alco- 
hol flame will volatilize most of these satisfactorily. The 
chlorides are preferable to all other salts of these metals, 
because of their greater solubility in water and ready 
volatility in flame. The carbonates of Li, and one or two 
others, are more easily obtained than the corresponding 
chloride, and though not as soluble, can be used. Stron- 
tium, and several other refractory salts, will volatilize if 
first treated with strong H 2 S 4 . The oxy hydrogen flame, 
described in Chapter IV., may be used for volatilizing more 
refractory compounds. But a pocket spectroscope has not 
sufficient magnifying power for the proper examination of 
such resulting spectra. Very refractory substances can be 
volatilized by keeping the electrodes of a large Buhmkoff's 
coil wet with the solution of such compounds, and passing 
a rapid succession of sparks. At least four Bunsen cells 
should be connected with the coil. 

246. Absorptive Spectrum. — For the exhibition of this, 
an easily controlled beam of sunlight from a porte lumiere 
is necessary. 






SPECTRUM ANALYSIS. 103 

Prepare a cell for the absorptive fluid as follows : Cut 
from thin window-glass two plates, 3x4 inches. Obtain 
at any rubber works two or three pieces of sheet rubber, 
from one-fourth to one-half of an inch thick, and 3x4 
inches in area, at a cost of 25 to 40 cents apiece. Cut out 
the centre of these rectangular pieces so as to form figures 
shaped like a in Fig. 24. These serve for the bottom and 
ends of the cell. At a brass foundry have four clamps 
cast of the shape of b for 10 or 15 cents 
each. The space between the prongs should 
be an inch, and the thread of the screw 
nearly as long. By means of these clamps, 
two at the bottom and two at the sides, 
fasten the rubber strips between the glass f tG 24 
sides. Place slices of cork between the 
ends of the screw and the glass. Cells so made have a 
great advantage over all others in that they can be taken 
to pieces and cleaned. Cells can be made by fastening the 
sides to bottoms and ends of strips of glass with marine 
glue, but they are apt to leak and are troublesome to clean. 
They may be filled with aqueous solutions of blood or a 
decoction of logwood or cochineal. The strength of the 
solutions and the thickness of the strata of fluids, through 
which the light is passed, will be found to affect the 
spectra. The spectroscope should be placed close up to 
the cell and directly in the line of the emerging beam. 




CHAPTEE XII. 

ELECTRICITY IN CHEMICAL REACTIONS. 

247. Use of Electric Current. — Many of the most im- 
portant analyses and syntheses of compounds are made, 
and many of the most beautiful and instructive experi- 
ments in the whole range of the study are performed by 
the use of the electric current and spark. 

248. The Apparatus necessary consists of the various 
eudiometers and decomposing cells described further on, 
an induction coil with a £-inch spark, and a Bunsen battery 
of four cells. The cost of the coil will be $ 8.50, of the 
battery about $ 2.00 per cell. 

249. Use and Care of the Battery. — It is best to avoid 
the nitrous fumes from the action of the Bunsen battery 
by using bichromate of potash solution in place of nitric 
acid in the porous cups. Prepare the solution by dissolv- 
ing 3 ounces of bichromate of potash in two quarts of 
water. The outer fluid is made by mixing one part of 
strong H 2 S 4 with ten of water. Use the " in series " 
connection, a carbon with the next zinc, etc. Keep all 
the metallic connections rubbed bright with enamel cloth. 
Never leave the battery standing after use. Take it to 
pieces immediately. Pour the liquid from the porous cups 
and rinse them. Bemove the zincs and rinse them thor- 
oughly in clean water. 

250. To Amalgamate the Zincs. — The zincs when pur- 
chased will be coated with mercury. This must be fre- 

104 






ELECTRICITY IN CHEMICAL REACTIONS. 105 

quently renewed to prevent the wear of the zincs and loss 
of potential by "coasting trade." Weigh out two ounces 
of mercury and add it to a mixture of four fluid ounces of 
II N O s and eight ounces of H CI, and place it under the 
hood. After the chemical action has ceased add 10 ounces 
more of H CI, and place the liquid in one of the glass jars 
of the battery. Dip the zincs into the liquid as deep as 
you desire to coat them. Do this work also under the 
hood or out of doors to avoid the corrosive nitrous fumes. 
If the zincs are small a less quantity of the liquid may be 
prepared, but it is economy to prepare in the proportions 
given. The liquid may be kept in a stoppered bottle and 
used for the same purpose more than once. After the 
zincs are once amalgamated a few drops of mercury occa- 
sionally poured directly into the outer solution, while the 
battery is in action, will unite with the zinc and keep the 
coating intact for a long time. Both fluids weaken rapidly, 
and therefore should be frequently renewed. 



VOLUMETRIC ANALYSIS BY ELECTRICITY. 

251. Decomposing Cell. — Fig. 25 represents a cell for 
the electrolysis of water. Provide a small tumbler and 
two 6-inch test-tubes of exactly the same volume. 
Determine this equality by filling one with water 
and pouring into the other. Secure the tubes in 
position by looping a small wire around them 
and binding the ends down over the edge of the 
tumbler. For electrodes cut out pieces of plati- f^25. 
num foil, \ by 1 inch. Fasten to these platinum 
wires about 3 inches in length, drill the tumbler for the 
admission of phial-corks and pass the wire through them 
as shown in the figure. It is not necessary to solder the 




106 ELEMENTARY CHEMICAL TECHNICS. 

wires and electrodes. Make little slits in the foil. Pass 
the wires through and head them down. This cell is 
inconvenient for the electrolysis of corrosive fluids, as it 
necessitates wetting the hands in testing the gases pro- 
duced. A cheap and admirable cell for many experiments 
is shown in figure 26. 

252. Universal Electrolyzer. — Cut off from about J-inch 
glass tubing two pieces exactly 7 inches in length. Fit 
sound corks in one end of each tube. Obtain, 
at any druggists, two of the patent metallic stop- 
pers used on toilet bottles for bay-rum, tooth- 
powder (select perfect ones), etc., and screw them 
into the corks. Dip the corks in melted paraf- 
fine and sink them into the tubes a little more 
than " flush." Fill in the space thus made above 
the corks with melted sealing-wax. Select a 
good tumbler of clear glass. From sheet-cork 
rio.26. cu |. a pj ece to fit the tumbler. Pass the two 
tubes and a thistle tube through this cork, thrusting them 
about an inch beyond the under surface. Prepare elec- 
trodes and platinum wires as in the cell described above. 
The larger the surface of the electrodes, the more rapid 
will be the action. Fit the cork into place, sinking it J 
of an inch below the surface of the tumbler and pour 
over the top enough melted sealing-wax or gum shellac to 
fill the depression. 

To fill the Apparatus. — Open the metallic stopper and 
pour the liquid into the thistle tube. As soon as the fluid 
reaches the corks in the tube, close the stopper. Be sure 
that no acids ever touch the metallic stoppers. In testing 
the gases j^our more of the liquid into the thistle tube to 
produce pressure, and open the cock. At p a quarter-inch 
hole is drilled and stopped with a phial cork. This is for 
draining the cell after using, and to let air out while fill- 
ing it. 




ELECTRICITY IN CHEMICAL REACTIONS. 107 

253. Analysis of Water. — Water can be made a con- 
ductor of electricity by adding about £ teaspoonful of 
sulphuric acid to the quantity necessary to use in either 
of the decomposing cells described. Use a four-cell Bunsen 
battery and connect the battery wires with the platinum 
wires by screw clamps (see Chap. III., Sect. 33). 

254. Analysis of Hydrochloric Acid. — The equal vol- 
umes of the gases will not become manifest for some time 
on account of the solubility of the CI in the fluid. It may 
be necessary to open the stop-cock of the H tube and let 
out the gas several times before the fluid is driven clown 
equally in both tubes. Use as concentrated acid as pos- 
sible. Wash out the apparatus after the experiment with 
care, especially the metallic cocks. The nascent CI may 
attack the platinum, but the action will be slight. Elec- 
trodes may be made of pieces of small carbon pencils, but 
are not necessary to success. 

255. Electrolysis of Ammonia. — Use the same cell in 
the same manner as in the preceding. Four Bunsen cells 
will do the work slowly. Another ready method for 
analyzing HgN is as follows: Use the apparatus in Fig. 29. 
Pass one of the platinum wires through a cork which fits 
into the mouth of one of the arms of the bent tube. Fill 
the tube with H 3 1S~ till it touches the cork. Make the 
terminal which is in the arm containing the cork the nega- 
tive electrode (i. e. connect it with the zinc), and H will 
gather under the cork. Connect the same electrode with 
the carbon, and N will gather under the cork. 

256. Synthesis of Water. — It is better to purchase a 
Ure's eudiometer for this work, price $ 3.50. But one can 
be made that will do fairly well. Bend a piece of glass 
tubing, 3 feet long (with a half-inch bore) into the shape 
shown in Fig. 27. (For bending large tubing, see Sect. 26.) 
Seal one end in a hot flame. On opposite sides of the tube, 



108 



ELEMENTARY CHEMICAL TECHNICS. 



two inches below the closed end, drill holes for the admis- 
sion of phial-corks. Pass platinum wires through the 
corks. Coat the corks with "stra- 
tena," and press them in firmly- 
The wires must be exactly opposite, 
^g- of an inch apart. Curve the wires 
into a loop outside of the corks. 
A barometer tube, if it does not 
diminish in bore toward the top, can 
be made into an excellent eudiome- 
ter. For making the divisions, see 
Sect. 27. 

To use the instrument, fill the 
tube with water by holding it in a 
nearly horizontal position, the open 
limb uppermost, and letting the 
water run in a small stream into the 
closed limb until the bend is filled. 
To introduce gas, hold the tube, with 
mouth down, in the water. Pass 
the desired volume, as nearly as can be estimated, up to 
the bend, and invert the tube. Insert the first. The 
strain of explosion is not so violent for the " home-made " 
instruments if an excess of one gas is used, as 4 parts of O 
and 4 parts of H. An excess of 2 parts of is then left 
after union* Leave three inches of air in the top of the 
open limb for an elastic cushion, and place the thumb over 
the mouth. 

The best apparatus for obtaining the spark is a large 
Kuhmkorff coil. Connect with the coil a single Grenet, 
or two Bunsen cells. Remove the brass electrodes and 
replace them with copper wire passing to the platinum 
loops in the eudiometer. It is well to merely lay one of 
the wires upon the platinum loop, that the reaction may not 




Fig.27. 



ELECTRICITY IN CHEMICAL REACTIONS. 109 

wrench out the wire from the tube. When all is ready- 
send a spark through the mixture. Kead results only after 
the water is brought to the same level in the two arms. If 
the tube is not graduated, the general principle of volu- 
metric union can be demonstrated by reading against a 
yard-stick, placing a mark on the stick and one on the tube, 
and making these marks exactly coincide at each reading. 
In lieu of a Kuhmkorff coil a most excellent substitute can 
be made, as in the figure, with a large Ley den jar previously 
charged from a plate or Holtz machine. / is a copper wire 
twisted around the outer coating of the jar, g hooks into 
the loop of the wire and passes up to one of the platinum 
loops. At b is a loop in the other copper wire into which 
a piece of glass tubing may be inserted for a handle to 
avoid the discomfort of accidentally receiving the charge. 

257. To Form Acetylene. — Use the apparatus repre- 
resented in Fig. 28. This consists of a tube of 1-inch bore 
and 20 inches long, a is a straight champagne cork settled 
in J of an inch below the rim and glued in with "stratena." 
The space above the cork is filled in with wax cement (see 
Sect. 58). At e and b the tube is bored for the admission of 
phial-corks through which are passed pieces of a 
carbon sticks, the size of a knitting-needle (ob- - i» 
tained of any electrician). The electrodes should 
touch. Wind the battery wires many times around 
the carbon electrodes. Place several inches of 
pure H in the tube over water. Pass a current 
from a battery of eight cells through for some 
time. Then press the tube deep into water, open 
the stop-cock and ignite the acetylene. 

258. To Decompose Marsh Gas, Acetylene, etc. — 
Prepare a tube similar to that represented in Fig. f ,G -28. 

28, using instead of the carbon sticks platinum wires, set 
•jJg- of an inch apart, or use a Ure's eudiometer. Shut in a 




110 ELEMENTARY CHEMICAL TECHNICS. 

measured quantity of the gas to be analyzed over mercury 
or water and pass through the apparatus a rapid succession 
of sparks from an induction coil. Note the change in 
volume of the gas and the gathering of tiny bits of C on 
the platinum wires. 

259. Decomposition of Salts. — A description of the de- 
composition of a few salts will be a sufficient guide for 
work with as long a list as may be desired. For all such 
experiments use the apparatus represented in Fig. 29. The 
shape of the tube there given is better than that of the 
ordinary U-tube. Make it of a piece of 
tubing, 8 inches long, with a half-inch bore. 
The electrodes are of platinum foil, J by 1 
inch, and all of the wires entering the tube 
should be of the same metal. The number 
of cells to be used depends somewhat upon 
the results desired. For simple acid and alkali analyses 
two, three, or four cells may be used, the larger the number 
of cells the more quickly the work will be done. Make 
a strong solution of the salts in water. 

(a) Binary Salts. — 1. Fill the tube with a solution 
of ammonium chloride deeply colored with a fresh solu- 
tion of purple cabbage. Note the beautiful red caused by 
the acid at the + pole, and the green from the alkali at 
the — pole. 

2. Use a clear solution of potassium bromide. Note the 
yellow fumes of bromine at 4- pole. Then use more of the 
same solution colored with cabbage decoction. 

3. Use first clear solution of potassium iodide. The 
iodine gathers at + pole. Second, same solution with 
dilute cold solution of starch. Blue compound of starch 
forms at + pole. Third, same, colored with cabbage solu- 
tion. Acid gathers at +pole, alkali at — . 

4. Sodium chloride solution colored with purple cab- 
bage. 



ELECTRICITY IN CHEMICAL REACTIONS. Ill 

(b) Xit rates. — Use lead, potassium, and ammonium 
nitrates, each colored with the cabbage solution. 

(c) The deposit of metals upon the — pole. Use two 
Bunsen cells. 

First a clear solution of iron sulphate. 

Second, same of copper sulphate. 

Third, of lead acetate. 

Fourth, of silver nitrate. The last two, if the action is 
slow, will show the beautiful spangled crystallization called 
lead and silver " tree." To a solution of lead acetate add 
enough acetic acid to cause the cloudiness to disappear 
before passing the current through. 

If the current is strong and the action rapid, the metals 
separate from the salt in a loose flaky powder. By a slow 
action copper, silver, lead, and gold may be separated so as 
to show their metallic properties. 

260. Separation of a Metal by the Action of another 
Metal. — Several metals may be separated from their salts 
by the weak electrical action of another metal suspended 
in a solution of the salt. 

Make an aqueous solution of lead acetate in a test tube. 
Dispel the cloudiness with a few drops of acetic acid and 
suspend a well-cleaned strip of zinc in the liquid. In this 
way the lead tree will form in a few hours more beauti- 
fully than by the use of a battery. 

The silver tree is formed by suspending the zinc strip 
in a solution of the nitrate. 

Silver will separate from the nitrate in an exceedingly 
beautiful manner by placing 2 or 3 drops of mercury in 
the solution. It makes the famous "Arbor Dianae." 

Separate tin from its chloride and iron from its sulphate 
by suspending strips of zinc in their solutions. 

A strip of copper, zinc, or iron suspended in a solution of 
mercuric chloride sets the mercury free. 



112 ELEMENTARY CHEMICAL TECHNICS. 

Dissolve As 2 3 in dilute H CI and suspend a clean cop- 
per wire in the solution. The wire will become coated 
with As. 

261. Separation of Antimony and Bismuth by the Action 
between Zinc and Platinum. — Place in the bottom of an 
evaporating-pan a strip of platinum foil, £ by 1 inch (an 
electrode). Upon the middle of the foil place a single zinc 
granule so small that it will not project beyond the edge 
of the platinum. Pour in water enough to cover both, 
without disturbing either. Add H CI till a brisk evolution 
of H takes place. Then add a few drops of a solution of 
tartar emetic for antimony, or of bismuth chloride for the 
latter metal. The metal will be deposited on the platinum 
in a black, finely divided form. 



ELECTROPLATING. 

262. General Directions. — Both electroplating and elec- 
trotyping are arts in themselves, and demand long practice 
and experience for the best results. But it is by no means 
difficult to make class illustrations of both arts, and by 
following directions minutely to do creditable amateur 
work. No expensive apparatus beyond battery cells is 
needed. For a plating cell cut off the neck and upper 
part of a junk-bottle so as to leave a square vertical-sided 
vessel with a capacity of about a quart. A square or rec- 
tangular shape is preferable, but a quart stone-china bowl 
will do. Lay stout, clean, copper wires across the vessel 
and suspend the anode and kathode from these by rather 
fine copper wire. The object to be plated is made the 
kathode, i. e. is connected with the zinc, and a piece of 
the same metal as that in the solution is made the anode. 

263. To Clean the Articles. — Anything to be electro- 






ELECTRICITY IN CHEMICAL REACTIONS. 113 

plated must be scrupulously cleaned, — must be chemically 
as well as physically clean. Clean off the surfaces of the 
metals with emery paper, crocus, or the various polishing 
powders in common use. Then wash the pieces thoroughly 
in a solution of caustic soda to remove all traces of oil or 
grease, and dry with a piece of soft cloth. After this stage 
avoid touching the surface of the metals with the hands. 
Next, wash the articles in dilute H 2 S0 4 , then in pure 
water, and they are ready to be quickly transferred to 
the plating bath. 

264. Readiness of Different Metals to receive Plating. — 
There is a great difference in the comparative readiness 
with which different metals will receive metallic coatings, 
and in the solutions from which they will take the plating, 
as well. 

German silver is plated most readily. Brass is a very 
good substance with which to practise plating. On the 
other hand iron and zinc cannot be plated in a copper 
sulphate solution with a battery. Many metals will 
receive the coating after being dipped in a solution pre- 
pared by dissolving mercury in nitric acid diluted with 
three volumes of water, and after the metal is dissolved 
doubling the volume by the addition of water. 

265. To Copper-plate. — Use a strong solution of copper 
sulphate for the bath and maintain its strength with an 
anode of clean sheet copper of about the same area as the 
article being coppered. If the solution seems to weaken 
rapidly, add a few drops of H 2 S 4 which will go directly 
to the anode and cause it to dissolve more rapidly. Hang 
the electrodes parallel about an inch apart. 

266. To Silver-plate. — The bath is a solution of silver 
cyanide. The solution may be purchased for about $ 2.50 
per quart. This will be advantageously doubled in volume 
by the addition of water. (A half-pint will do a good deal 



114 ELEMENTARY CHEMICAL TECHNICS. 

of plating.) Or it may be prepared as follows : Make 
solutions of potassium cyanide and three times its weight 
of silver nitrate in equal volumes of water. When the 
salts are completely dissolved pour them together. After 
the cyanide of silver precipitate is "formed, redissolve it by 
the addition of more potassium cyanide solution, and the 
clear solution is ready to be used as the bath. For want 
of a piece of pure silver a silver coin may be used for the 
anode, but after a time the copper with which the coin is 
alloyed works into the solution to the detriment of the 
latter. 

267. To Nickel-plate. — For the bath purchase an am- 
moniacal nickel sulphate and make a weak solution in 
water. Or make an aqueous solution of the ordinary 
sulphate crystals and add aqua ammonia till the solution 
smells strong. Add a little more ammonia from time 
to time. A piece of pure nickel must be obtained for the 
anode. 

268. For Gold Plating purchase a few grains of gold 
chloride. Make a solution of 1 part by weight of gold, 10 
of potassium cyanide, and 100 of water. Use a gold coin 
for anode. 

269. Plating by Chemical Replacement. — Silver may be 
deposited as a mirror on glass by the action of a tartrate 
salt on silver nitrate. To a solution of silver nitrate add 
weak aqua ammonia, drop by drop, till a permanent cloudi- 
ness appears. Place some of this in a clean watch-glass, 
add a little of a solution of " Kochelle salt," and heat the 
glass very gently. Place it on a sand-bath to heat. A 
silvered concave mirror can thus be made. 

To gild on glass dip a clean glass rod into a solution of 
gold chloride and heat the wet rod. 

Nickel plating is quite practicable by chemical replace- 
ment. Place a strong solution of zinc chloride in an 



ELECTRICITY IN CHEMICAL REACTIONS. 115 

evaporating-pan and dilute it with three volumes of water. 
If the precipitate of the salt appears, redissolve it by add- 
ing H CI. Heat to boiling and drop in a very small pinch 
of zinc dust. Add a solution of nickel sulphate till 
the liquid is a deep green. Then drop into the boiling 
liquid the article of brass to be plated (cleaned with the 
care and in the same way as for electroplating), together 
with a few little pieces of zinc. Let the contents of the 
pan boil for ten minutes or more. 



ELECTROTYPING. 

270. General Directions. — The article to be electrotyped, 
if it is a conductor of electricity, may be hung in the bath, 
and after it has been covered with a sufficiently thick coat 
the metal stripped off, and itself hung as the kathode. 
The coating that then gathers will give lines of the model 
in relief. The practical method, however, is to take an 
impression of the object to be electrotyped in wax, gutta- 
percha, or plaster-paris, and to use this cast for the kathode. 
The last mentioned substance is the best for the use of the 
amateur because it gives the sharpest cast with the least 
trouble. 

Select a new unworn sharp lined silver half-dollar as a 
good object with which to begin the art of electrotyping. 

271. Preparation of the Cast. — First clean the side of 
the coin to be copied and rub over it a very little oil that 
the cast, when dry, will not adhere to it. No expensive 
moulding-box is needed. From a sheet of heavy writing 
paper cut out a strip ^ of an inch wide and 3 or 4 inches 
long. Lay the coin down upon a table and measure round 
its circumference with the paper. Cut off the strip just a 
little longer than the periphery of the coin and glue the ends 



116 ELEMENTARY CHEMICAL TECHNICS. 

so that the paper loop thus made will just fit closely down 
over the coin. Make sure the oiled side of the coin is up 
and slip the paper band over the coin, making a shallow 
box with silver bottom and paper sides. A small rubber 
band stretched over the paper makes it fit the coin more 
closely. Make two little holes in the paper rim about ^ 
of an inch apart. Select a small copper wire, 2 or 3 inches 
long. Pass one end of the wire in through one hole and 
just back through the other, and bend it so that the part 
of the wire within the box shall fit up close against the 
rim. Mix plaster of paris in water to the consistency of 
rather thick cream and pour it over the coin. After 2 or 
3 hours the cast will be dry and can be taken out. If the 
cast is sharp, it may be used; if not, try again. If the 
copper wire was set in the box properly it will be firmly 
imbedded, but not completely buried, in the plaster. With 
a knife scrape away the plaster a little so that a clean 
surface of the wire can be seen the entire distance that it 
is imbedded. 

It now remains to make the cast impervious to the water 
of the bath and, over the surface of the impress, a con- 
ductor of electricity. In an evaporating-pan melt some 
pieces of a parafline candle, and set the reverse surface of 
the coin in the hot wax. The latter by capillary action 
will rise through the cast and spread over the entire sur- 
face. The darkening color will mark the progress of the 
wax on the surface. 

272. Making the Cast a Conductor and Placing it in the 
Bath. — Cut off from a piece of pure plumbago and from 
a cake of " stove polish " (the stove polish alone will do, 
though not as well) about equal amounts. Place the two 
substances in a mortar and grind them together to a very 
fine powder. Keeping the cast warm enough over the 
lamp to soften the wax, with a camel's-hair brush apply this 



ELECTRICITY IN CHEMICAL REACTIONS. 117 

powder to the face. Success depends upon the thorough- 
ness with which this part of the work is done. Rub and 
rub the plumbago upon the face till every part and line of 
the mould has a dark metallic lustre. Carry the plumbago 
surface faithfully over the edge to the wire so as to insure 
good electric connection. Hang the cast as the kathode 
and a clean piece of copper as the anode in a strong solution 
of copper sulphate. Use one large Bunsen cell. A type 
thick enough to peel off should form in 48 hours or less. 



INDEX. 



Absorption Spectrum, 102. 
Acetylene, 67. 

decomposition by elec- 
tricity, 109. 
formation by electric- 
ity, 109. 
Acids, to dilute, 39. 
Acid stains on clothing, 42. 

nitric, on skin, 43. 
Air, Atmospheric Pressure, f 3. 
carbon dioxide in, 53. 
composition of, 53. 
vapor of, water in, 53. 
Alkalies, action of, on skin, 43. 
Alkali Metals, 86. 
Aluminum, 91. 
Ammonia, 56. 

combustibility of, in 

oxygen, 57. 
decomposition of, 58. 
electrolysis of, 107. 
Ammonium, 88. 

amalgam, 88. 
hydrosulphide, 88. 
Ammonia, solubility of, in water, 

57. 
Antimony, 83. 

chloride, 83. 



Antimony, combustion in chlorine, 
59. 
mirror, 83. 

separated by action be- 
tween zinc and plati- 
num, 112. 
Apparatus and Glassware, List of, 

6,13. 
Arsenic, 81. 

combustion of, 83. 
silver nitrate test for, 82. 
sulphide of, 83. 
Arsine, 81. 
Aspirators, 24, 25, 26. 

Barium, 88. 

peroxide, 89. 
salts in pyrotechny, 88. 
Baryta-water, to prepare, 41. 
Battery, care of, 104. 
Bismuth, 94. 

chloride, 95. 

combustion of, in chlo- 
rine, 95. 
separated by action be- 
tween zinc and plati- 
num, 112. 
" Blanc Fixe," 89. 

119 



120 



INDEX. 



Blowpipes, 34. 
Borax Bead, 84. 
Boracic acid, 84. 
Boron, 84. 
Bromine, 63. 

starch compound, 64. 

experiments with, 64. 
Breathing chlorine gas, 42. 
Burns from acids, 42. 

phosphorus, 43. 
and scalds, 43. 
Burning clothes and person, 42. 

Cabbage, purple solution, to pre- 
pare, 41. 
Calcium, 88. 

carbonate, decomposition 
of, 88. 
Calomel, 92. 

Capillary action in wicks, 72. 
Carbon by distillation of wood, 66. 
reducing power of, 67. 
dioxide, absorption of, by 
water, 70. 
acid nature in 

water, 70. 
decomposition of, 

70. 
in fermentation, 

71. 
from monoxide, 75. 
preparation of, 69. 
properties of, 69. 
monoxide, preparation of, 
74. 
Casselman's Green, 97. 
Cast, preparation of, 115. 
Chamelion Mineral, 95. 
Charcoal, decolorizing power, 66. 

porosity of, 66. 
Chemicals, List of, 7, 14. 



Chlorine, 59. 

decolorizing and bleach- 
ing power of, 60. 
direct union with hydro- 
gen, 60. 
tetroxide, 63. 
water, 68. 
Combustion, 70. 

proof of products, 72. 
weight of products of, 
73. 
Compound blowpipe, 47. 
Copper, 97. 

chloride, 97. 
dioxide, 97. 
hydrated oxide of, 97. 
nitrate, 98. 
plating, 113. 
protoxide, 97. 
protosulphide, 97. 
Cork-borers, 32. 
Corks, to bore, 37. 
Cyanogen, 75. 

Decomposing bell, 105. 

Deflagrating-spoons, 33. 

Dialyzer, 85. 

Drying-tubes, 33. 

Dutch Liquid, preparation of, 62. 

Electric current, use of, 104. 
Electricity, apparatus for, 104. 

in chemical reactions, 
104. 
Electrolyzer, universal, 106. 
Electroplating, general directions, 

112. 
Electrotyping, general directions, 

115. 
Ethylene, 67 
Evaporating solutions, 38. 









INDEX. 



121 



Filtering, 38. 
Fusible Metal, 94. 

Gas-cock, 28. 
holders, 27. 
jars, tubulated, 31. 
Gases, to collect, 35. 

difficulties of collecting, 36. 
to dry, 39. 
to transfer, 36. 
Generators, 26. 
Glass, bending, 21. 
boring, 18. 
to close tubes, 23. 
cutting, 19, 20. 
etching, 22. 
grinding, 19. 
stoppers, to remove, 39. 
tubing, supply of, 18. 
Gold, 99. 

green color of, 99. 
plating, 114. 

Heating, 3. 

glass vessels, 37. 
iron stand for, 31. 
Hood, 5, 12. 
Hydrobromic acid, preparation of, 

64. 
Hydrochloric acid, decomposition 
of, 62. 
electrolysis of, 

107. 
preparation of, 

62. 
relation to 
combustion, 
62. 
solubility in 
water, 62. 
Hydrofluoric acid, 59. 



Hydrogen, 44. 

diffusibility of, 44. 

dioxide, preparation of, 
52. 

disulphide, 77. 

to purify, 45. 

tones, 44. 
Hydriodic acid, 65. 
Hypophosphorus acid, 81. 

Iodide of mercury, 65. 
Iodine, 64. 

affinity of, for phosphorus, 

64. 
preparation of, 64. 
starch compound, 64. 
Uluminating-gas, 68. 

power of flame, 73. 
Iron, 96. 

hydroxide, 96. 

salts, precipitates of, 96. 

sesquioxide, 97. 

Labelling chemicals, 17. 
Laboratory, cost of, 9, 16. 

table, 3, 10. 
Laboratories, the two, 2. 
Lac sulphuris, 77. 
Lakes, 91. 
Lamps, alcohol, 31. 
Lampblack, formation of, 67. 
Lead, 93. 

chloride, 94. 

dioxide, 93. 

iodide, 93. 

" pyrophorus," 94. 
Lecture-table, 4, 11. 
Lime cylinders, 48. 

water, to prepare, 40. 
Litharge, 93. 



122 



INDEX. 



Litmus-paper, to prepare, 41. 

solution, to prepare, 41. 

Magnesium, 91. 
Manganese, 95. 

dioxide, decomposition 
of, 95. 
Marsh-gas, decomposition of, by- 
electricity, 107. 
Marsh's test, 81. 
Mercury, 91. 

precaution in "working 
with, 91. 
Mercuric iodide under the micro- 
scope, 92. 
oxide with phosphorus, 
92. 
Metals, 86. 

readiness of, to receive plat- 
ing, 113. 
separated from salts, 111. 
Methane, 67. 
Mixed gases, 47. 

Nickel-plating, 114. 
Nitric acid, decomposition of, 55. 
preparation of, 55. 
oxide, 55. 

gives up oxygen, 56. 
Nitrous acid, to form, 56. 

oxide, 55. 
Nitrogen pentoxide, 56. 
tetroxide, 56. 
trioxide, 56. 

Oxygen, 45. 

combustibility of, 47. 
heating the mixture, 45. 
precautions in preparing, 

46. 
to purify, 45. 



Permanganate of potassium, spon- 
taneous combustion of, 95. 
Phosphine rings, 80. 
Phosphoric acid, 81. 

anhydride, 81. 
trioxide, 81. 
Phosphorous acid, 81. 
Phosphorus, 79. 

combustion of, in 

chlorine, 59. 
precaution in hand- 
ling, 79. 
red, 79. 

spontaneous combus- 
tion of, 80. 
Photography, 90. 
Pipette stand, 30. 
Plating, by chemical replacement, 

114. 
Platinum, 98. 

dissolved in " aqua 

regia," 98. 
melting of, 98. 
oxidizing power of, 98. 
sponge, 99. 
Plumbing, 13. 
Potassium, 86. 

chlorate, formation of, 
63. 

Receptacles for gas, large, 28. 
Rooms, selection of, 1. 

Sand-baths, 32. 
Salts, electrolysis of, 110. 
Scheele's green, 83. 
Sealing-wax, to prepare, 41. 
Silicon, 84. 

flouride, 84. 
Silver, 89. 

coin solution, 89. 



INDEX. 



123 



Silver, mirror, 90. 

nitrate with charcoal, 90. 

with phosphorus, 90. 
oxide, 90. 
plating, 113. 

salts, action of light upon, 
87. 
Sodium, 86. 

amalgam, 92. 
combustion of, in chlorine, 

87. 
combustion of, in oxygen, 

87. 
experiments with, 87. 
melted in hydrogen, 87. 
protection from pieces of, 
86. 
Soldering, 39. 

Spectra of different metals, 102. 
Spectroscope, to adjust, 100. 
care of, 100. 
kind of, to use, 100. 
Spectrum analysis, 100. 

tubes for solu- 
tions, 101. 
Storage-closets, 4, 11. 
Strontium, 88. 

salts in pyrotechny, 88. 
Sulphide solutions, 77. 
Sulphur, 76. 

dioxide, 78. 

bleaching action 

of, 78. 
condensation to 
a liquid, 78. 
plastic, 76. 

octahedral crystals of, 76. 
prismatic crystals of, 76. 
trioxide, 78. 



Sulphuretted hydrogen, 77. 

decomposi- 
tion of, 
77. 
water, 77. 
Sulphuric acid, 78. 

experiments with, 
79. 

Test-tube holders, 31. 
Tin, 92. 

chloride, 93. 

dioxide, 93. 

perchloride, 93. 
Turpentine, combustibility of, in 
chlorine, 60. 

Wall-papers, testing of, for arsenic, 

82. 
Wash-bottles, 33. 

Water, decomposition of, by sod- 
ium, 86. 
expansion of, below 39.2° 

F., 49. 
gases in, 50. 
mineral salts in, 49. 
organic matter in, 50. 
physical properties of, 49. 
supply of, 2. 
synthesis of, 107. 
weight, ratios of oxygen 
and hydrogen in, 51. 
Water-baths, 32. 

Zinc, 91. 

combustion of, 91. 

to prepare granulated, 42. 
Zincs, to amalgamate, 104. 




■ I fc> 

■ 




